I have swelling in my left arm above the wrist to my elbow and my left leg below my knee, on the right side. What could cause this? Do I need to see

Exam needed. Swelling of the forearm is quite unusual unless there has been a recent injury causing bleeding inside the area. If no trauma then a blockage in a vein is suspected. Swelling in the lower leg could be due to poor vein valves or pheblitis. I recommend that your Physician see you for diagnosis and treatment.
Unusual. Very unusual to have swelling in one arm and one leg. A medical exam would be needed to figure that out.