Few audis are used to dealing with the specialized needs of musicians. Hearing aids and audis are focused on speech comprehension.
If you have not already bought hearing aids or if you are considering buying new ones, ask your audi to contact the manufacturers of the hearing aid models that you are considering in order to find out the “input headroom” (There may be a more technical term for this). The idea here is that if your hearing aid has insufficient ability to accept the loud signal produced by live music your hearing aid will clip (distort) the signal right when it enters the hearing aid. The hearing aid will then send a clipped signal to the signal processing phase of the hearing aid and then out into your ear. Obviously not good.
Widex and Oticon are known for high input headroom. Phonak used to (and maybe still does) have significantly lower input headroom. Input headroom is not something most audis are used to being concerned about. But in my opinion it is absolutely crucial to a musician.
Have your audi set up a separate program for music performance (it will probably work well for music listening, too). For this separate music program, in the programming software have the audi turn off all compression and speech comprehension enhancements.
Also have your audi reduce the feedback suppression settings to as low as possible without the hearing aids producing feedback in a normal situation. Feedback suppression works by the hearing aid detecting a sustained note and then introducing a frequency modulation that interrupts that sustained note. The hearing aid can’t distinguish between feedback and a sustained musical note. So the feedback suppression causes a “trill” or “warble” that is especially disconcerting to a singer. With the feedback suppression minimized you might experience feedback when someone hugs you or gets close to your ear. If you experience feedback too often, ask your audi to increase the feedback suppression settings incrementally until you have the right balance between eliminating the “trill” effect and eliminating occurrences of feedback.
Lastly, do a web search for “Marshall Chasin”. He is an audi in Toronto who specializes in fitting hearing aids for musicians. He has some helpful articles online and in audiological trade magazines. Good luck!