Sometimes the injury is not so obvious so you could have hurt bone unknowingly. This pain can also be related to a muscle tendon or even the nerves – ulnar or radial. Nerve inflammation would cause pain, numbness or tingling lower down the arm as well. First try to immobilize the arm or at least use it minimally. If the pain subsides, you know that it more likely to be muscle or tendon related. Also try to stop leaning on the hand and this may also stop pressing and irritating any nerves. You should get this checked up. See your doctor as soon as you can.

Some of these symptoms are possible side effects of your medication but another possibility is related to the heart as in angina. Refer to the article on heart chest pain. Given your history, this is not something you should ignore. An ECG stress test (stress ECG) is important here and you should see a cardiologist for this. Despite the fact that the pain eases and there may be no other symptoms, further medical investigation is most definitely warranted before a more serious condition strikes. Another possibility could be related to the position you sleep in or even the number of pillows you use. This could cause muscle spasm with referred pain down the hand or lead to a pinched nerve. Diabetic neuropathy/neuralgia (nerve pain due to diabetes) is another possibility but first exclude any heart related disorders.