Hi thanks for asking question. First you could have simple musculoskeletal pain as you are suspecting.It mightbe by heavy exercise or weight lifting.Rest and analgesic with hot compression useful for it. Second rule out respiratory problem if suspicious symptoms present like cold or sore throat with fever.X ray and pulmonary function test seems to be useful for it... PFT useful for diagnosing and differentiating restrictive and obstructive pulmonary disease. If still no benefit then we will do further work up according to more history and physical examination. Take care......