After firing 10 shots on a firing range with ear plugs my right ear feels as if it is blocked. This was my first time & will be my last.

Ear Wax. You may have packed some cerumen into the deeper portion of the ear canal by inserting the plugs. See your doctor to get evaluated, with a possible ear irrigation.
See below. This is one of those problems where a visit to your doctor is necessary to figure out what's going on. Only after a thorough evaluation, including examination and possibly labs and other tests, can your doctor correctly diagnose you and treat you effectively.