There's lump under neck, sore throat and headache. what could be wrong with me?

May be viral: Infection or strep, etc. For significant sore throat with swollen tonsils / lymph nodes – see physician ; get a strep throat test/ culture. If you have strep throat, antibiotic therapy is imperative to prevent future complications. Consider tylenol (acetaminophen) or nonsteroidal anti-inflammatory medications. Saltwater gargles: mix 1 tsp salt in 8 oz warm water – gargle several times a day.