Unlike most of my posts this is not something in which I actually have a solution but rather, it is something that I am experiencing myself at the moment and don't really have an answer. I have temporary solutions but nothing permanent unfortunately.
I suppose that if anything, this is a warning to people in their 20's or 30's that are lifting with reckless abandon and no regard to safety. I'm in my 40's and I did very little in the way of stretching, warming up, or even paying attention to when my body was screaming back at me. I am now paying the price in a variety of ways.
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I chose this picture because even though it is most likely a lady in the pic, this is exactly what I am dealing with. There is a nagging and never-ending soreness in that area that is just beyond my reach over one of my shoulders extending into my upper back.
Sometimes at night I wake up and the pain appears to have moved to include also my neck and upper spine, which is something that concerns me.
I can't say for certain but it really wouldn't surprise me if at least some of this comes at the hands of lifting irresponsibly and ignoring warning signs about certain pains that I have around my own spine. I certainly hope that it isn't spinal but unfortunately I fear that it could be.
When you lift the way that I did in my 20's and early 30's you feel invincible. I know that I did. I wouldn't pay much attention to posture and I never wore one of those back-braces because I thought that guys under 220 lbs that did wear one looked stupid.
Do yourself a favor so that you don't end up like me: Go ahead and be ok with looking stupid because it is better than feeling terrible basically all the time.
One reason why I am relatively convinced that it isn't muscular in origin is because I do not have limited range of motion - my arms have the same range of motion on both sides. There is no particular angle that triggers the pain, it is just a tight feeling that is there all the time, even when I lie down.
It is impossible for me to know the exact cause for this but I would imagine it is from years of overloading without concern for proper form. Proper form became very important to me in my early 40's and I have stuck to it very closely ever since. Just like a smoker quitting smoking when they turn 45 though, it might have been too late for me at that point.
I think it is very important for people to really look at fitness and especially weight-lifting, as the dangerous sport that it actually is. My situation is rather minor compared to others that have abused themselves considerably more than me, but it is still a very real problem. Just be careful out there. You can stay fit and get reasonably ripped without causing long term harm.