Had slight pain near my left tonsil for ~3 weeks now. Bit of a cough, slightly sore throat and hoarse voice. No difficulty swallowing. What can it be?

Tonsil trouble. It is a good idea to have this evaluated. It can be a viral infection, bacterial infection, allergic symptoms, apthous ulcer, growth or polyp. Be sure to get it evaluated so you know what is causing this. :)