Hello, welcome to the forum. Have you spoken to your doctor about this? That would be important to do if it is a chronic situation. A simple issue that can cause ear pain and muffled hearing in one ear chronically is a build up of ear wax. Are you sure this isn't going on? There are products sold at the drug store that gently remove ear wax, ask the pharmacist to direct you. Debrox is an example. Here's an article of other reasons people might get ear pain like you describe. https://www.webmd.com/cold-and-flu/ear-infection/why-does-ear-hurt#1 Have you had your teeth checked any time recently? That can cause ear pain as well. Best to check in with your doctor to find the reason. Let us know what happens.