Hi, Thanks for your question. Please rate my answer if you are satisfied. The fluid behind eardrum accumulates when your Eustachian tube (a tube that connects your middle ear cavity with your throat) is either blocked or is malfunctioning. The usual cause of this is frequent and excessive mucus production because of allergies or repeated infections. Therefore, the nasal spray and allergy meds are helping your congestion and solving the problem. But you have sore throat, your nasal spray was doing the trick by taking off one of the causes of your ET dysfunction but now you have another cause. This needs to be treated as well. You may need some antibiotics. The allergy treatment with nasal spray and pills usually improve the function of ET but in cases where it doesn t, there is a mild surgical procedure where they insert a very tiny tube (called grommets) into your eardrum under local anesthesia. It ventilates your middle ear and dries it out improving the symptoms. Indigestion is unrelated to the this condition and you can consider home remedies or diet balance. Sometime all you need is plenty of water, fiber and some antacids. So, I suggest you to get back to your doctor and talk to him about treating your sore throat and also about the symptoms coming back. I hope I have guided you good. Feel free to contact me. Regards.