You mention being a 'mountain biker' and you get pins and needles. With mountain bikes in mind, I'm wondering if that could be your cause. When I was more able bodied I used to be a keen cyclist and enjoyed my time out. Until I decided to opt for a mountain bike and within a few months I started to get pins and needles in my hands from the wrist down .. then in the crotch area. It would go off within 30mins of dismounting but then I noticed it in my hands within 30mins of behind the car's steering wheel, so I consulted my GP and was told it was possibly vibration/jarring damage from the mountain bike.
I now suffer with arthritis so biking is not on my daily menu, but the tingling still starts up when driving my car.