My 2 and half mnth old baby is crying whenever i put bottle nipple in her mouth. can anybody help me with this?

i went to the doctor and he said nothing is wrong with her. no mouth, ear or throat problems.. she s exclusively bottle fed and drinks 24-28 oz of milk per day. she has even decreased the amount of milk since this thing has started. she s fine with the pacifier but only fussy about the milk bottle. the nipple pore is fine and milk flow is normal.