anyone ever have a nagging muscle pain in leg?

Granted i have played sports all of my life and worked out most of it, I know what a sore body feels like. However, about 2 years ago during a non lifting time (that followed a pretty intense couple of months of stonglifts 5x5 in which you squat each lift), i started to notice my left quad was tender almost as though i had been lifting.... I would roll it and it would feel good as i would normally roll my muscles. It had the "hurt so good" feeling. The pain was not related to a current lift or anything of that nature. However, throughout the last 2 years or so, the pain would come and go at times. The pain has never gotten worse or kept me from daily activity, but it has the "oh i have a sore muscle feel to it, literally a 1/10 pain). Has anyone ever experienced this? I looked it up online and nearly scared myself to death with it talking about soft tissue sarcoma, etc. That usually has lumps and stuff, which i do not have anything like that going on. I actually started squatting again this last week and the pain seems to be gone or at least blending in with the current muscles under repair.

When i would roll it, the pain seemed to disperse throughout my leg, much like when you are rolling a normal muscle. I guess Im trying to say that the pain wasn't in a single place much like a broken bone, fracture, etc.... it feels as though its definitely muscle related as manipulation to it feels good. Could there be a build up of lactic acid in there that has stuck around? Thanks for advice everyone.