Hi. I have this terrible aching throbing pain under my right armpit and towards my breast. When I press the muscle near my breast I get this shooting pain under my arm. I have also been having shooting pains at night down my right arm and in my shoulder.
Thanks for your question on Chat Doctor. I can understand your concern. Possibility of musculoskeletal pain is more because you are having tenderness (pain on touch). But better to get done chest x-ray to rule out Pulmonary causes for chest pain. If chest x-ray is normal than possibility of musculoskeletal pain is more. So avoid heavyweight lifting and strenuous exercise. Avoid movements causing pain. Avoid bad postures in sleep. Start painkiller and muscle relaxant Chat Doctor.  Apply warm water pad on affected areas. You will mostly improve in 1-2 weeks time. Hope I have solved your query. Wish you good health. Thanks.