Do I have multiple sclerosis, I’ve been having a lot of pain in my legs and a lot of muscle spasms?

I’m a 19 year old male , take no medication. Could I still have multiple sclerosis if I tested negative? So about a year ago I was having vision problems in my right eye and decided to see an eye doctor. When he took a look at my eye he saw swelling of the optic nerve and sent me to a neurologist. After getting a bunch of tests done they diagnosed me with optic neuritis and had no idea what caused it. Optic neuritis is sometimes an early stage of ms so they sent me to the ER to have an MRI and a blood test (not sure what for exactly it was along time ago) both tests came back negative. So it’s been almost a year and a couple months ago I’ve been having a lot of pain in my legs and a lot of muscle spasms way more than usual. I’ve also been feeling very depressed lately don’t exactly know why , but I’m usually a very happy guy. My leg pain occurs mostly when I’m laying or sitting down and it ranges from my upper/behind my knee to about mid-calf level and severity on a scale of 1-10 is about an 8. I’ve also been feeling very weak and extremely tired most of my days, and at times my left leg sometimes “gives out” but not entirely. I do experience some numbness /tingling but haven’t worried much about it just cause I thought my leg/hand falls asleep. I haven’t bothered to see a doctor about it because I feel I’m just going to waste money and it’s not going to be anything. I’m 19 years old and am worrying that the tests I had didn’t catch anything and wasn’t sure if I could still possibly have ms. Would appreciate some insight!