I just started the mobility exercises, too. I bought a foam roller at Walmart last week, but couldn't find a lacrosse ball anywhere. Do sumo deadlifts make you insanely sore?
I think it pretty much started when I started eating healthy, drinking plenty of water and exercising. I think it's got to be related to that. I've browsed the bodybuilding forums on this topic (I know, not the best source of information, but it's people with similar eating and drinking habits and activity levels) and it seems to be very common, even 5+ times a night. Some of those guys have been tested for diabetes and prostate problems and everything. I think I may just get checked for those two soon just to eliminate them. Administering simple tests that I specify and giving me the results should be within my doctor's ability level.