Does extra weight cause....

I suggest you start out gently - especially if your back is problematic. I know when I don't/can't be as active I very quickly lose my mobility and get increased joint pain. When this happens with me I up all aspects of my general activity (eg walking a lot more, low impact workouts, swimming) until I feel better. It happens very quickly. When your mobility improves and pain lessens is the time to return to your intense workouts. While calorie counting make sure you hit your protein goals if you want to rebuild muscle.
ETA if my weight goes up my joint pain returns pretty quickly - keeping active and keeping my weight down is the only thing that works for me

First, congratulations for caring enough about your health to ask and showing you want to do something to change it.

Before everyone starts demanding research articles: I'm no expert on any of this but I think it's easy to address some of your concerns with common sense.

Extra weight causes lots of issues in your body in the cell level and beyond. It's why people get high blood pressure, diabetes, etc things that can be reversed with better diet and lower body fat. Knees suffer, your back can, your feet, everything. We're not built to carry excess weight.

I have lost 40lbs in the past and gained back 50lbs. So yes, it's possible to lose, be embarrassed, and get back up. For me, idc what people say about my body because I've been fat and subject to jokes, abuse, bullying about it all my life. I care about me and my health now, not others'.

Personally, I don't believe in chiropractic practices for back pain that isn't related to serious back conditions or injury. I think back pain and other body pains come from poor posture, muscle weakness, muscle tightness and imbalances throughout the body as a result of poor posture and too much sitting/inactivity. Sometimes arthritis is the problem and no amount of stretching or chiropractic visits will heal inflammation in your spine.

Last year, I went to a chiropractor for upper back pain every other week. The 'cracking' felt good but after 2 months, I was in worse pain that when I went in! Stopped going, looked up posture correcting exercises, videos, articles, and walk more. I feel much better now. The best exercise for me was using a bar or broom stick to increase shoulder mobility. We're hunched over so much of the time with our phones or in front of a screen, or just sitting improperly much of the day. Our back muscles become stretched and weak, the shoulder and chest muscles become weak and tight, pulling us forward and downward causing back pain. Your chiropractor isn't going to tell you this. They want your and the insurance company's money.

More movement should help your pain. I'm not sure about your current activity level but less activity could be the reason you're hurting. Your body may be too stiff from not getting exercise so you might find that over time your pain lessens. I'd look into stretches and massages. Your hip flexors could also be to blame. If your back hurts when you walk it could be issues with other parts of your body like hip flexors. Your hip flexors could be tight and pulling your spine out of line, causing pain in your hips and back (this is what I'm in PT for now).

Anyway... I'd start small and get your weight down. If that doesn't help, see your doctor. If the pain is unbearable, see your doctor now for their recommendation. Just know, depending on the doctor, they may want to give you a pill first... I'd run. A good doctor imo wants to get to the root cause of what's happening in your body, wants to know what your diet is like, and what you do for a living that may be causing problems without starting you on a new pill unless they think it's absolutely necessary. (I was given a low dose of an antidepressant for frequent headaches. Turned out it was actually because I was eating too much sodium and drinking no water. Duh.)

Best of luck to you.

Honestly, I don't think that you gained that much muscle in a year, unless you were eating at a surplus and doing strength training, and it's unlikely that you lost a lot of muscle in 4 months either eating at a surplus (if you were a man, maybe). It's probably the fat that you gained that covered the muscles.

But I hear you about having a hard time maintaining your weight when you don't exercise... I have the same problem. I'd start slow, probably just at home to start with online videos (if you're worried about people watching you) but definitely see a doctor first to figure out your back problem.

Lots of good answers; just wanted to chime in and say people always have this idea that they have to constantly progress. In reality, your weight, your fitness level, the things you choose to focus on - these will all be periodic. They’ll change over the course of your whole life, maybe some things you’ll love and stick with and focus on forever, but most things you enjoy and take something from in the moment, and leave it when you want to work on something else.

I suggest you make health and happiness the things you keep with you always. Because, who really cares if you have to modify burpees? Anyone who’s focusing on you enough to see that you’ve “gone backwards” needs to spend more time working on themselves. We all face injuries, challenges, and life changes; no one should judge someone else, or more importantly - themselves - for doung a healthy thing for themselves and working to the best of their current ability.