I had a sharp pain tonight in the cold air when I breathed in deeply. I have mild asthma but I doubt it was that. I also have, forgive the spelling, suspected Rhamdomyalisys (or something like that) from a drug interaction between cholesterol pills. I got off statins and Niaspan back in September.It did feel muscular but it was hard to tell.
If you suspect Rhabdomyolysis, it is better to check blood level of Creatine kinase (CPK level). If you are on Statins for high cholesterol level it is better to consult your doctor for an alternative. Sometimes you can have deep pain when breathing in deeply due to a muscle catch/pull. If your asthma control is good I would have a conservative approach, as long it is not impairing your day-to-day activity.