Around the beginning March of this year, I injured my back at the gym. Well, to be honest, I assume that's where I did. I was doing dumbbell bench presses when an employee announced over the loud speaker that the gym would be closing in a half hour. So I quickly grabbed the dumbbells I was using (~75lbs) off of the ground with TERRIBLE form. There wasn't any pain or anything, the only thing that tipped me off to the fact that I may have injured myself was that I KNEW I picked the weight up incorrectly. Anyway, I had some soreness in my lower back that went away after a couple of days. So, assuming I was fine, I got back into the gym and did some squats.
Fast forward to today, and since that day I have not been able to sit down for more than 15 minutes without feeling fatigue and what I can only describe as "clenching" in the muscles in the middle of my back. Usually this pain is located on either the left or right side of the spine dead center (vertically) of my back. Sometimes the pain seems to relocate in between my shoulder blades, but usually is located where I described above.
Another thing worth mentioning is that during the beginning I felt kind of like there was something blunt jabbing into my spine where the muscle pain is located today. This still happens sometimes, but isn't as pronounced anymore.
I've been to the doctor, who said I probably tore some muscle tissue and was experiencing muscle spasms. He prescribed me flexiril and ordered me to rest my back. After about a month and a half of not getting better, I went back and got some XRays (note: not an MRI) done, and the doctor said that there weren't any signs of anything serious, so an MRI wasn't warranted.
I've been back to see him a few times, and he more or less throws some ibuprofen at me and shews me out of his office. I don't feel like I'm getting anywhere and I haven't gotten a decisive diagnosis. I'm only 22 years old, and before March of this year I had never had any sort of back issue my entire life. Am I describing anything common? I'm sorry if I rambling, it's 3am and I can't sleep because my back is bothering the crap out of me.