I have been having sciatica. I thought it was just a pulled muscle but as you said the pain goes down my leg. I have just been taking some advil.
For a long time I never connected the pain in my leg with my back,
(not to be confused with the pain in my neck which is my girl friend)LoL
I used to drive a lot and it would come and go so like you I thought it was muscle pain.
Then the pain came and stayed and I said hey maybe I should ask my doctor.
They took an X Ray which showed I had deteriating discs in my lower back mystery solved.
He prescribed some nifty stuff called
neurontin/gabapentin which I take 3x a day.
I also have some muscle relaxers and oxycodone for those heavy days.
The oxy is more for my kidney stones though and I try to avoid taking it.
The pain from the stones is soo severe that even with the oxy it's almost intolerable.
You need to get thee to the Dr or chiropractor.
The Gabapentin works pretty good I don't recommend the oxy it makes old men (me) feel young and that's not a good thing. LoL
I see why it can be addictive so I only take it in extreme situations.