Pain in the left side of the back.?

I used to use a lot of fat burners,testosterone boosters and worked out a lot.About 1 year ago I worked out my back with the cable row and suddenly I heart like something snapped on left side of my back.I thought it was a muscle and in few days I will be fine.Since that incident pain is not going away,just kind of dull pain and what is most surprising,I became extremely sensitive to the caffeine and other stimulants.I mean after really strong coffee I can get dizzy,feel like I am passing out and etc.I went to see a doctor and have been in ER FEW TIMES.The number of doctors checked me in and out as far as heart condition,stroke and other vital problems I may have and didn't find anything,nothing.After all they said I have severe anxiety.I was very surprising about that.Any ideas what I am going thru,or may be some one have a similar problems?It is ridicules,sometimes after strong coffee I feel like shortness of breath,dizziness,difficulty to swallow ,dry mouth,etc.Any ideas?