Hi Dear , Welcome to HCM. Understanding your concern. Thanks for your query . It is normal to have sour taste in mouth during pregnancy . The most probable reason for sour taste in mouth during pregnancy is hormonal changes . For sour taste i would suggest you to suck on mint candy and eat yogurt as it is probiotic. This taste is temporary and go away with time in case of pregnancy . As far as bump behind tongue is concern there could be many reasons like hormonal changes , lack of enough vitamin, weakened immunity and stress . So i would suggest you to start taking multivitamin supplement under expert advice , eat more citrus fruits, maintain proper oral hygiene , do betadine mouthwash rinses and try to keep your stress level low . If condition persist or get worse consult your doctor for proper examination and to rule out other cause . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari