“What could be the cause of my throat pain?”

Many different things. Infection, reflux, post nasal drip, laryngeal lesions such as a vocal cord polyp or cyst, or simply cervical muscle strain cause your throat to hurt when you swallow. Best to have a doctor evaluate you and if needed they will send you to an ENT to have a laryngoscopy in the clinic for an exam of the larynx. At your age, mild odynophagia (pain with swallowing) is going to be from a common tonsillitis, or untreated reflux disease.

Hello,

There can be multiple ENT related reasons. I would recommend seeing an ENT specialist as this needs a good exam and detailed history.
Thank you.

Dr. D