Can strep cause pain on only one side of the throat?

Sometimes. Sometimes, strep throat will cause more pain in the left or right side of one's throat, but symptoms usually generalize to both sides of the throat within a few days. This can happen with any kind of throat infection, not just with strep. Doctors have a 5-minute test they can do in the office from a throat swab, to diagnose strep throat. Antibiotics like amoxicillin are used to treat strep throat.