You are definitely not alone. 🧡
Mine is right eye too, from ON in 2016, and yes....behind the eyeball - I usually think of it as eye socket pain behind the eyeball.

For me the eye pain is definitely related to light exposure - AND the usual MS trigger suspects: stress, heat, over-exertion. So the glasses really help with the light exposure trigger for me. The eye pain is the first symptom I notice, so if I'm not wearing my NeuroTint glasses, I put them on immediately. Often I wear them as a preventative. My damage from ON was so severe that even with the NT glasses I can't go into stores like Walmart anymore. I can do short Costco trips since their lights are higher IF I also wear a baseball cap with a brim.
I recently released a MS.UNDERSTOOD podcast episode on MS visual impairment if interested. There I share all the research as well as many possible avenues for solutions, since we are each unique. Hope it helps you as much as it helped me! https://rss.com/podcasts/msunderstood/ 🧡

Yes. I have definitely experienced this from ON...and ongoing. For me it's usually linked to inflammation. I recently got a migraine cap - it's a stretchy ice pack that surrounds your head. Since this doesn't happen to me often I've only used it once so far, but it really helped. Prior to that I experienced relief using peppermint essential oil (topically, but not near my eyes, on my head!, and by popping peppermint beadlets in my mouth and breathing deeply through my nose). I also LOVE my NeuroTint glasses. They reduce eye strain and protect my eyes (I have a lot of damage from ON that is permanent). Since I got those November 2019 I haven't experienced the issues as much so they are a great preventative solution for me. I hope you find your solutions soon! I know how significantly that pain can disrupt our lives. 🧡

Do you have migraines? They can be felt in interesting places.

I have had optic neuritis and continue to have pain behind my eye on a regular basis and my optic neuritis happened 4 years ago

Ive experienced this back in 2015. My Left eye was in horrible agony pain. It felt like it was in the back of my eye all the time. And when I had went to the eye doctor I had stated that my vision had decreased and that I was having severe pain off and on That's when they took a look and they said that my optic nerve was pale. Then they stated what could be behind that which was MS which left me baffled because I didn't even know what the hell that was. Upon seeing a neurologist after three spinal taps and the fourth being a needle ultrasound one based yeah that hurt like hell and cause nerve damage a little bit in my back from that and then found out that I had it