There are a couple of different possibilities that may be contributing to your problem.
First, you may have an increased need for amplification on the right ear that isn’t being properly addressed. When you turn the hearing aid up to the level you need, sound may be leaking out of the ear piece and going back into the microphone, causing feedback. If this is the case, it’s a simple fit issue. The more sound we put into the ear, the more we need a good seal in order to keep the sound where it’s supposed to go. Your hearing healthcare professional can help you ensure that you are wearing your hearing aid correctly. You may also need to reassess your hearing aid for a different style of fit. In most cases, this can be done with your existing devices. For example, if you’re wearing an open-fit hearing aid with a dome, you may need to switch to an ear mold. Or, if you’re wearing a custom hearing aid, you can usually have it reshelled for a reasonable cost.
The second possibility is that the problem is related to an obstruction in the ear canal. Wax build-up can reflect sound back out of your ear where it’s picked up by the microphone, resulting in feedback. Schedule a visit with your provider to check for a proper hearing aid fit and to look for obstructions in the ear canal.