Recently i've noticed yellow jelly like lumps mixed in with my semen, also during/after ejaculation there is a burning like pain ? i'm 18 and a virgin

This happens: Nobody knows why, but some guys get this and it lasts for some time. I can't address the cause of the burning pain beyond suggesting that these do a little bit of damage to the super-delicate urethral mucosa. I trust you have no symptom to suggest prostatitis. Good luck -- and saving the best for that one special woman on that one special night is a great idea.