horrible burning sensation after sex

Hi,
Welcome to ehealthforum,
The symptoms that you describe could suggest possibility of vaginal infections, vaginal dryness/lack of lubrication, hormonal disturbance, sensitivity to seminal fluid proteins etc. The exact cause can only be made out after careful evaluation. Consider visiting your doctor/gynecologist at the earliest for thorough examination and further evaluation to look for the underlying cause for the symptoms that you describe. Treatment as indicated (based on examination findings and investigations results) would be started to help you control the symptoms. Avoid vaginal douching, use of harsh soap or perfumes in the area. Use loose cotton undergarments and avoid use of tight fitting clothes. If infective cause is detected, and if you are sexually active, get your partner also treated simultaneously, and avoid having intercourse while being on treatment to prevent chances of re-infection. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.