Hello elmogreeneyes. Welcome to healthcaremagic.com.
A broken thumb does not cause a pinched nerve at the c5-6 level. That is coincidental.
The fall could have caused the pinched nerve at the same time that your thumb was broken. The nerve intervations of c5-6 may explain the pain in the left arm that radiates to the thumb, however, those nerve paths do not have a connection to the difficulties of your left leg.
Unilateral swelling (swelling on only one side) indicates a disease process that is not related to your heart. Some causes of unilateral swelling include fractures, ankle sprain
(blood clot), cellulitis
), venous stasis dermatitis
(skin infection due to pooling of fluid in the lower extremity).
If your leg is hot and red, go in for emergency evaluation of your swelling, if not, contact your family physician for evaluation of your condition.
Be well, Dr. Kimberly