I suffer from hearing issues all the time. Mine are sinus issues. Plus I live at about 1600+ feet elevation, so my ears are constantly plugging,popping,... I think I might have termites, I see floaters in my vision daily. I do sometimes feel a swish sound and then all goes silent, then a high pitch sequel sound, then my hearing comes back.
Not sure what causes it, I think it has to do with environment, age, maybe MS. I wish you peace and success with your search for an answer.

I have had horrible tinnitus for a long time that became significantly worse post optic neuritis, with eventually over a dozen different tones. My ears were often painful from lying on them when I woke up in the morning. ENT tested me and said my hearing was 100% and I'd just need to learn to live with the tinnitus. Then this February in a CranialSacral session, the practitioner gently applied pressure on my abdomen and my jaw cracked audibly! Since then I have only two tones left and they are sporadic, not constant. All this to say, don't give up hope! I use helichrysum essential oil which helps with drainage - so it definitely seems to be sinus, vagus nerve, jaw alignment issue for me. Hope you find your solution soon - I know how horrible it can be! It was so bad for me at one time I had to rely on reading lips to really hear a conversation well. XX

I’d get in touch with the doctor who’s treating or monitoring your MS! Asap! Some doctors believe that new symptoms can be treated effectually and that permanent damage can be headed off. I wouldn’t waste time with that one!

Yep, tinnitus in the ears makes it hard to hear certain tones. And if I go out and there is loud noise, crowds, whatever; everything will overwhelm my hearing. It can actually get painful. I finally started carrying earplugs for that situation.