Feeling of a lump in my throat. one side at the back of my throat looks swollen but there's no pain. what could this be?

Is it red?: Redness, swelling & pain are the hallmarks of viral or bacterial pharyngitis (inflammation of throat/pharynx) or tonsillitis. Fever might also be present, along with other typical symptoms of upper respiratory infection (cough, nasal congestion, runny nose, ear ache). If you don't seem ill, I think you can watch it. Might be inflammatory tissue that will recede on own; if doesn't go away, see doc

Get it checked out: 'Lumps' in your throat may be something simple like an enlarged tonsil or could be due to more serious issues like tumor. Lack of pain suggests that there is no infection or inflammation, but doesn't tell us anything more. This is where a visual exam becomes important. You should get this lump checked out by a medical specialist or doctor.