Could Bactrim (sulfamethoxazole and trimethoprim) cause chest tightness. Chest is sensitive to touch. If so, do I need to stop taking it? No other side effects.

Depends. Chest pain/tightness can have many causes and many implications. Some are minor and some can be life threatening. If you are allergic to Bactrim (sulfamethoxazole and trimethoprim) this could cause some of the symptoms, however no rash? More information-a complete, accurate history and physical is recommended by your doctor if you indeed have these symptoms. Please go to the emergency room for full assessment.