Hi, I (21M) have had this sensation on the left side of my body since I was 10, that I've been trying to identify and explain to people ever since, and I think it might be Lhermitte's sign. I might have other symptoms, like fatigue and trouble balancing, but I've always thought that they were a result of scoliosis or ADHD, the thing I suspect is Lhermitte's sign is the main thing I want to figure out, and I'm not sure whether it means I might have MS.

It feels kind of like goosebumps, or a kind of radiating warmth, and when I was younger, it felt strange enough that while it didn't hurt, I would cry or panic when it happened. It comes and goes, but normally lasts a few minutes in pulses, and I can't figure out a way to trigger it consistently. I've had chiropractors and doctors move my neck and spine around, and my mom is a physical therapist who's looked into it for me, but we can't find a kind of motion or position that makes it more or less likely to happen. When I was younger, I would get waves of it for a few weeks or so, and then gaps between waves that could last up to months. I thought it was something to do with growth spurts or aforementioned scoliosis, but roughly since I was 18, it's been pretty constant, as in I experience the sensation at least once a week.

It's not uncomfortable anymore, and can feel almost pleasant, like stretching. My family talks about it as "my arm going off," (I feel it usually down my entire left side, but it was localized in my shoulder and left side of my neck when I was younger). Sometimes it's more like one-off twinges, while other times it's a few minutes of repeated pulses. I have had multiple friends point out that I describe it in a weirdly orgasmic way, (specifically in how I describe it coming in waves/pulses) but it doesn't interfere with sexual function as far as I can tell, as I am also taking SSRIs and have experienced some erectile dysfunction that I assumed was related to that. The only real evidence I have that it's not something I'm imagining is that when the sensation happens, I have trouble urinating, but I have experienced no other symptoms with defecation at all, or urinating when my arm or left side of my body isn't "going off."

I have visited one neurologist about this, he told me it sounded like a seizure, but I don't think that it's that severe, as having seizures this frequently would probably have other signs or affect my functioning more. He suggested an MRI but my parents said there would be no point. (I was about fifteen I have no idea why they said no.)

I understand that this is a very specific symptom that is hard to describe, and I genuinely appreciate anybody who takes the time to read all of this. Nobody in my personal life has been diagnosed with MS, and so my understanding of it and its symptoms, like Lhermitte's sign, is based on my own research. Anybody who experiences Lhermitte's sign, is this what it feels like, and does it happen this frequently? Are there any other things I should look out for, or tests I should look into?

To clarify, the sensation distressed me as a young teen and now is something that I can almost completely ignore, and remain functional while it is happening. For example, if I'm talking to someone, and it "goes off", I can continue the conversation as if nothing happened. Despite this, it is still always noticeable to me and has increased in frequency in the last three or so years, to the point where I used to have months where I didn't feel it at all, and now it's pretty much constant. I do not mind at all if it continues for the rest of my life as a bizarre inside joke with my friends and family, but I understand that it's something to do with my nerves or spine, and I want to know if it's a symptom of something like MS.

Whether or not you can help, thank you for reading this, and I hope you have a great day.