Every year i swallow 3 different antibiotics for tonsils, but it always comes back, what might be the cause of that?

Doctor can check: Inflamed tonsils can be checked by a primary care doctor (or an ENT doctor) to see what the cause might be. Sometimes it is a strep throat bacterial infection, in which case antibiotics would be needed. Other possibilities include viral infections (colds, mono, the flu), stomach reflux, allergies, etc... A doctor can examine the throat to treat it. Meanwhile, lozenges may lessen discomfort.

Common issue: The skin surface helps you avoid germ invasion on most of your body surfaces. The digestive system, starting at your mouth/throat is a different tissue that is more absorptive & likely to be invaded by germs. Your tonsils are there to trigger your immune system to germs it can fight. You may be more susceptible to strep, but if you are taking abx without testing they may be just viruses.