What could cause a constant feeling of fullness+slight pressure 1in to right of adams apple for longer than 3 months? Strep throat test negative. Ty!

Neck fullness. Fullness and pressure in the neck/ throat can be from an external factor an enlarged lymph node or cyst pushing on a neck structure, or from thickened secretions accumulating at the level of the adam's apple/voice box. See an ear nose and throat specialist for a thorough head and neck exam, including a direct look at the voice box.