I have something white on the tip of my uvula and sore throat for the past 3 days. sometimes it is hard to swallow. what is it? could it be serious?

Sore throat: This is probably a viral throat infection which will run its course in several days, but a rapid throat culture could be done to check for strep. See your Physician if symptoms persist or worsen. In the meantime try lozenges and/or gargles for soothing relief.

Pharyngitis: You have a sore throat or "pharyngitis" which can be caused by any number of viruses or bacteria. Strep is probably the most famous bacteria and should be screened for. Smoking is a risk factor for these infections because of the toxicities of smoke. Hope u can quit. Watch for worsening such as fevers, lymph nodes in the neck, etc. The white stuff by the way is pus- that's what the MD should swab