Stalled with Strong Lifts

Check your form first. OHP is very finicky for me. If I'm off at all I will fail. You also need to understand though that OHP is almost always the lift that people struggle with the most. Smaller muscles.

Second, if you're not eating enough you'll probably see issues with progression.

At my gym I see people regularly bench pressing, deadlifting and not uncommonly squatting. I, however, rarely see people doing standing ohp as it is a fairly difficult movement, so just by doing it you are one step ahead of most people! So well done!

Two things that has helped my OHP exceptionally is paused bench press and close grip bench press. The strict ohp is made difficult by many factors but working on a very explosive start makes it much easier! I've found pause benching help with this initial explosion.

It should also be noted that you are eating at a deficit so your strength is unlikely to increase much if at all. When it is increasing it will mainly be due to better form. As you are only on week 10 it's most likely just a small stall, it usually takes me weeks to add even a few pounds extra on.

One tip that may help put some extra weight on the bar is squeeze your glutes throughout the exercise. It will help keep you stable and I always find it gives a little bit of an extra drive, especially towards the end of the movement.

Use dumbbells for OHP. Start with the smallest ones, focus on the form and work your way up from there. Dumbbells will require you to stabilize the motion much more, so they will activate and develop all the smaller muscles really well, too.

A 45 lb OHP is a lot, especially if you weren't lifting before starting Strong Lifts. Switch to dumbbells until you are up to 45 lbs. I've been lifting for years and started Strong Lifts last summer after recovering from a shoulder injury. I started my OHP at 20 pounds and didn't even touch the olympic bar until I was on my 6th OHP day. The OHP has by far been my toughest exercise.

Sounds like maybe you started too heavy across the board. I know the program calls for just a 45lbs bar, but I feel that is geared for most men and some women when it comes to upper body. As others suggested, maybe start off with lighter weight dumbbells and work your way up to the bar. Beyond the bar, you need to invest in micro-plates if your gym does not have them. They are really cheap and can be found on Amazon for around $50-$60 for a set. Theses will include .25lbs to 1lbs plates so you can go up in smaller increments instead of the usual 5lbs jumps that the program does. The gist of the program is that a beginner can make increases every workout for a while (usually a couple of months) until things start slowing down. This is where you will stall, be able to increase some, stall, maybe stall again, fail, deload, try again, etc.... Going through this as programmed should take quite some time and normally one can run the full program anywhere from 6-12 months until running its course and needing to move on to something like Madcow (which makes weekly increases instead of "daily" increases as you are no longer a beginner, but more toward an intermediate lifter). This of course assumes all other variables are in place like nutrition, sleep, and doing the program without much interruption.

If you don't have microplates, you can also increase by adding reps for a while instead of weight.

Able to do 5 reps? Next time do 6. Then 7, then 8, then 9. If you aren't able to do the prescribed reps for all 5 sets, repeat that number of reps for next time.

When you can do the 5 sets of 9 reps successfully, add 5 lbs. and start back at 5 reps per set.

From the stronglifts website--

Stronglifts wrote:

The empty bar can be too heavy. I had my girlfriend do goblet Squats with a kettlebell, kb Deadlifts and db bench/presses. Now she Squats 50kg for 5×5 (her body-weight). You’ll need fractional plates. Adding 2.5kg/5lb each workout is too much on the Bench and Overhead Press. This is because women tend to have less muscle in their upper-body than men. My girlfriend used increments of 1kg/2lb from the start on Bench/Press.

Read more: http://stronglifts.com/5x5/#What_does_52155_mean

Grab the Stronglifts app if you can. It will guide you through deloads and when to switch to 3 set of 5. You are not likely to find fractional plates at any local sports store, unless you have one that specifically carries a lot of olympic weight gear. Amazon is a good place but they are much more expensive than the regular buck a pound