<s>[INST] Hello ~ My husband works out with weights. Although he didn t notice anything unusual during his workout last night, he awoke this morning with pain in his upper arm accompanied by a very hot to the touch area and pinkness of the skin. His arm hurts even when resting it completely. It doesn t appear to be either the tricep or bicep muscles, but rather something in between those muscles. Best way to describe the area would be where you would most comonly place a tattoo on your upper left arm. I was thinking possible bicipitl tendonitis but what would cause the area to be hot? [/INST] Hi,Thanks  for  your query.According to your description , pain over your upper arm seems to be due to tendonitis(inflammation of tendon) and that is the cause of hot area.I advice you to give you rest to the part affected, take anti-inflammatory drug like motrin 1tablet with food as and when required (upto 4 tablets daily) to reduce pain and inflammation and consult your doctor for thorough examination and rule out any infective cause.I do hope that you have found something helpful and I will be glad to answer any further query.Take care </s>