I have a weird shoulder problem. After cycling for "a while" continuously (where "a while" starts at around 6 miles and goes up from there), I will sometimes start getting tingling and pain in my right shoulder. It doesn't always happen, and it isn't particularly consistent in terms of distance or speed ridden. Once it starts, though, it will persist and tend to get worse over time. In extreme cases it may even persist in a much more mild form in following days.
The weird part, aside from the inconsistency in distance and speed, is that it's only my right shoulder; my hands, legs, arms, left shoulder, etc., are all fine. It's also not exactly my shoulder, even. It's actually a spot right along my spine, about 2-3 inches below my neck.
The pain isn't sharp like a bone pain or pinched nerve; it's more of a tingling ache.
I realize I should see a doctor about this, and intend to once I get decent general practitioner in my area, but does anyone have any ideas in the mean time? I have a flat-bar commuter bike, but changing hand positions doesn't seem to have much effect.