Have tonsilitis, feverish, taking antibiotics, painful body, headache, can't eat well. now i have chest pain. is it related?

Tonsillitis: Sounds like you have a bacteremia. Yes its all probably related - if you have been on antibiotics they may need to be changed.

Have it evaluated: A person with chest pain needs to be evaluated and treated appropriately. Multiple possible causes may be: heart attack, esophageal reflux, anxiety, musculoskeletal, pneumonia, pulmonary embolus, and aortic dissection. Have it evaluated right away to prevent potential serious complications.

Possibly: You may have some pleurisy (inflammation of the long of your lung) which can happen with many illnesses- more often with viruses (which are not improved with antibiotics). You may also have chest wall pain - which comes from muscles/ligaments/tendons- can happen from coughing a lot, or with general muscle aches with illness