I've been having tongue pain for about a month now. happens almost every day could heartburn cause mouth pain?

Perhaps: You could be having some reflex which is irritating your tongue. See gastroenterologist for heartburn and dentist to examine your mouth. Gerd can cause other dental problems.

Tongue pain: What type of pain is it? Is it a burning or chemical type pain or is it a deep like muscular aching. I would go to your dentist or oral surgeon to have it checked out. Pain is usually a call to action for something, especially if it is difficult to put your finger on a cause. I would get it checked out sooner than later.