Duration of symptoms. It depends on 1) duration of symptoms 2) other symptoms like pain, weight loss 3) age 4) history of tobacco or alcohol abuse. If duration has been short (less than 2 weeks)with no weight loss and other symptoms of a viral infection (fever, chills) - then it is likely nothing to be concerned about. If long duration of symptoms (>2 weeks) with weight loss - it should be evaluated.
See your doctor. Your doctor can do a swab of the throat to check for step throat. There are many reasons that can cause difficulty swallowing. Check with your doctor.