IDK in your back??? A arm or leg could be loss of circulation, but in your back??? When does this occur, is it after a specific workout? I'd probably just work through it, but I hate doctors. I can't recommend that for anyone. MRI or CAT scan or whatever they would have to do to see nerve damage might be expensive on ya. Even with insurance. Find yourself a rehabilitation place, or a doctor that is more specialized in sports injurys etc. Going to some old school jackass that doesn't understand our pursuit for beef won't wanna dig anymore than they have to. Yea prob. just tell you to stop lifting for awhile and see if it stops. If you find someone who knows sports injurys and how to treat them, and what causes them, you will find your fountain of youth. lol. If they say your ok, I'd say work through it then. I'd haveta be dying lol, before I went to the damn doctor.