I'm going through the same thing right now... started out with what i thought was a shoulder injury, it hurt to sleep on that side. Then one night after rolling on that side in my sleep i felt a knot under my shoulder blade, near my spine.. and i was praying it wasn't/itsn't a disc issue. I just started back to the gym after taking over 12 weeks off! .. it sucks, b/c all my exercises on major body parts have turned to shit... are alot lighter than I'm used too.. and the ONLY thing that would get rid of the pain (and only turn it into an annoying throb), was aleve.
Now, I will say.. one night i got lucky and somehow laid a certain way, woke up and as i turned my back cracked in 4 places, and the pain in some of the areas lightened without aleve...
Let me ask you this.... b/c you said on your feet all day... I have VERy FLAT FEET. .. about 6yrs ago, I went to a foot doctor who told me my feet were the worst he's seen in 20yrs of medicine. Needless to say, he told me that if I didn't use orthotics (molded foot incerts), which cost over 400 bucks a pair i might add), that I would have about 10yrs before my knees would need total replacement.
Needless to say, I never got the orthotics, but he told me not to wear flip flops, sandles, or any flat shoes... he also told me if i goto the beach, that i need to wear sneakers... never run on the beach, and do low to no impact cardio... he told me that i WILL have back, shoulder, disc, and knee problems... if i didn't do this....
... are your feet flat? .. if they are, you need some sort of orthotics to fit the arche in your feet, it will re-align your spine and the way your body holds its weight against gravity... i'm dealing with the pain right now... and it sucks.. i don't have insurance either, and won't get an MRI or even bring it up to my doc before i have insurance due to the 'prior existing conditions' rule... but it hurts.