burning back pain and acidity

Hi,
I have a peculiar problem from last 2 years. Actually it all started after I twisted my back while playing. There was pain in back for few days and I thought it is normal since I played after long time.
But later I started experiencing burning sensation on the middle right section of the back and burning turns to pain if it becomes heavy. Later I used to get burning sensation on left leg and left hand. This burning sensation also depends on how I sit. It increases based on the way I sit. One more problem is I experienced increase in acidity due to this burning and pain problem. Even I take medicines for acidity it never goes. And recent thing I observed is based on poistion I sit acidity reduces and increases.That was strange.This might be due to some compression or due to damage.
I had all testing like X-Ray,MRI,Ultra sound scanning and all look normal. I am really worried now because of this. Doctor had given medicines for nerves strength and nothing worked. I have been suffering from this from last 2 years and really tired of this. Is this because of Nerve impingement due to injury or what might be wrong which actually doing all this. I can feel some pain and something wrong on right-middle part of back but no problems in bones. Please tell what might be the problem and please help me out.
Please do reply.

/Mahesh