According to the symptoms that you have mentioned, the most likely diagnosis to your muscle pain and fatigue is Myofascial Pain Syndrome. Which produces muscle pain and tenderness, similar to fibromyalgia, is among the symptoms of this condition. Muscles' trigger point gets developed, causing pain in different areas due to the compression against the nerves. The muscle would then become loosened up or weaker. The key features of this disorder include physical therapy sessions, injections of trigger point pressure, and a certain kind of drug guidance to manage stress.

You may be suffering from a blood clot in your leg as a result of the accident. Injury to the leg causes blood to pool and form a clot causing swelling, redness, and pain. This is serious because the clot may break free and travel to other parts of your body. Elevate your leg above your heart, apply ice, and take a break. When the pain persists or becomes severe, go to the nearest hospital immediately.

Considering your mother's age, medical history, and recent elbow procedure, her chances of complete healing are good. However, arthritis can sometimes slow down recovery. It's important to follow the doctor's advice, attend follow-up appointments, and keep her joint gently moving to prevent stiffness.