Redness in throat. Need to performed.

  I have sore throat or what would I say it does't s red back throat with little bit pain while swallow . I consulted the doctor and had a throat culture which turns to be negative , then I went to a ENT specialist and he prescribed calithromycin or cloff tablet,one gastic tablet and a pain killer but with no luck at all.Then went to RMLhospital there doctor adviced amocyllin for 6 days and cefixime tablet for 5 day but result was the same no effect at all, then doctor adviced me not take any further antibacterial tablets and adviced me to do gargels only.  It's been 2 months I am suffering from this redness in throat and I am bit tensed about this issue.  Please suggest what problem could it be and please let me know what tests need to performed.