Girlfriend swallowed pills, she had a coughing fit and is now complaining about right hand back pain lingering and throat pain. is this something to be greatly concerned about? esophagitis?

She likely has a sore spot where the pill abraded a point in the esophagus. It can trigger swallow spasms or pain for a transient period. These are usually superficial/self-heal in a few days. If she has trouble drinking fluids/eating it may be worth a trip to the urgent care folks. A firm diagnosis would require a scope down the throat & pictures. I doubt anyone would do so unless major symptoms