What's the difference between early arthritis and poor blood circulation in the feet? i feel like both are a little painful. thanks for your help!

Pain: Arthritis is inflammation in the joints and their attendant structures, poor circulation implies poor blood flow into the feet , both conditions can be painful.

Totally different: Arthritis denotes specific abnormalities limited to the joints. Poor circulation indicates a vascular problem which has nothing to do with the joints. It is doubtful that at age 21 you have vascular problems. Also the type of pain and the circumstances under which pain is felt will be different in vascular disease or arthritis.