I got blood drawn a couple days ago vein on forearm feels a little swollen and tender, could working out today cause pressure or vein to be aggravated. i dont want to go to hospital if im just being sensitive?

This could be an inflammation of the vein caused by the venipuncture. It is not a serious condition. It's treated with hot applications. You could also take an anti-inflammatory medication like ibuprofen. See your physician as needed.

Swelling and mild tenderness are associated with a venepunture and not related to exercise. It is caused by a little blood escaping outside the vein and will gradually disappear. Good Luck