Pain and swelling inside of arm above elbow.. seems like its up the side of my arm (inside) what can cauee this? no injury to my knowledge does this sound like a blood clot?

Arm pain: A blood clot in a vein is a possibility in view of the swelling. Certain sport activities can cause this. Blood clots are dangerous and thus you should be examined as soon as possible, preferably in the hospital emergency room where prompt attention and testing are available. If needed, appropriate specialist(vascular surgeon, hematologist) will be called in.

Cellulitis?: If there is pain, redness or fever, you may have cellulitis, a skin infection; or lymphangitis (similar problem). These are often very serious ; you may need an antibiotic or even hospitalization. Get care soon. (This could be especially dangerous if you use drugs by injection in this area.) Good luck.