It is in no way a fact that marijuana is a stimulant. Some strains may have more of these qualities than others. Pain is nothing but you're brain interpreting signals. A lot of times it just tricks the brain into misreading those electrical signals. But you are kinda correct that to me it helps with nerve pain better than with shoulder or back pain related to a disc or whatever. Now I'm a novice at the different strains but I do know some help with this more than others.
In my case my spinal cord was not severed but due to 3 fractured vertebrae in 98 it had immense bruising and swelling due to it taking 6-7 hours to get me to The Med due to weather. Tupelo at that time while only 30 mins away by ambulance was not the level trauma center it is today. Emergency medicine has come a long way. Now they'd just give me a cortisone shot immediately for the swelling and I'd been playing ball a month later. But the swelling causes part of the cord to die. So now this is just a similie, but while the brain is constantly getting signals from below saying hey everything is good down here those signals never make it. So the body below the injury never gets the message back that everything is ok, carry on it becomes like a person on a cellphone on a long bottom loosing signal and ppl start talking louder thinking that will help. The brain never gets these complete communications. So it says Houston we have a problem and starts to panic subconsciously, hence the nerve pain. The cannibas calms all this hyperactivity over nothing down. So while it helps me rest, lot of it is just bc of the nerve pain gets worse when I stretch out and get still. I don't know why this makes it worse. But without the pain I get more natural sleep without needing medicine to sleep which turns me into a zombie. More natural sleep makes these nerve signals less intense the next day so that the pain during the day is less. Then it becomes a cycle. But when I have some I generally don't take use it during the day as I generally don't like the feeling, but this again would be more helpful if I could better choose the strain that had certain qualities. Maybe that helps in understanding my particular situation. I've been fighting this injury and the various medications for nearly 20 years now so I know what helps and what doesn't. This long posts probably needs numerous proofings but hopefully the point is clear.