My left leg a little more warm and swollen than the right. cramps&pain for weeks have had ddimer and ultrasound come back fine. should i headbacktoer?

Just see your PCP.: This sounds like something your primary care physician (PCP) should start working on. All the ED will do is repeat the U/S. If you have other medical problems, notice a rash, or if things are different from your first visit, than a return trip to the ED is warranted. Otherwise, your PCP try and sort this out further.

Leg pain: Rather than go to the ER it would be better to see your regular physician to determine what the cause of your problem is. You need continuing care.

Lymphedema: Your symptoms , of warmth and swelling of your leg may be associated with a condition called lymphedema. Normally, lymph nodes filter fluid as it flows through them, trapping bacteria, viruses, and other foreign substances, which are destroyed by special white blood cells called lymphocytes. Without normal lymph drainage, fluid can build up, and lymphedema can develop. Follow up with your PCP.