What Causes Persistent Pain In Throat?

hi I went to the medstop today for the second time this week with pharyngitis and this time I told them what was all the first time amd how the doctor on Tuesday gave me omixicillon to treat pharyngitis. And I had taken pills since wednesday which didn t help at all, my throat was hurting me today worse than Tuesday and Wednesday so, the dr gives me two shots in my hips one starts with an r and the other one starts with a d how long before I start to feel better? I was also prescribed different medicine and was told to stop taking omxyicilln