Hi there! I'm a 14 year old female, and for the past few days I've been feeling the same thing along with a few other symptoms. We went to the doctors and they told me I had a sinus infection, along with a swollen uvula, which is what the 'lump' or feeling in my throat is.
I suggest visiting the doctors to see if that' she the case, and from then on you can see what they suggest for you.
A swollen uvula could be from the cause of a dry mouth, or sore throat, so it's best to make sure there's nothin to wrong furthermore in terms of sinus/throat/lung health.
This discussion is from awhile ago, but I still hope this helps.