shoe insert recommendations for leg length discrepancies?

I've always turned my right foot in and kicked my right leg out to the side a little as I ran. If I pay attention to my form, I can keep this down to a slight pronation. In highschool, my doctor gave me heel inserts that also had some arch support, but I really didn't like running with them. I always stretch out pretty well after about a 1-mile warmup, and I've never had any injuries whatsoever in 15 years of running, except for getting shin splints when my shoes wear out, but that really doesn't count. As I start to add distance, though, I've noticed that my left foot bothers me a little after runs of 5 miles or more. This is just a mild pain in the outside of my left heel and along the top of my left foot in front of the arch. This confused me a bit, because I've always thought that my only problem is with my right leg. That is, I thought that my right knee didn't quite bend the right direction or something, and my real problem was just keeping that leg and foot straight. If I take a day off after 5+ mile runs, this is all a non-issue, but I don't like that option because I'm trying to get more serious about running. After looking around, I've found multiple sources of information that point to this as classic symptoms associated with Leg Length Discrepancies. The longer leg (my right) pronates and the shorter leg (my left) supinates. My right shoe (pronating foot) has a lot of wear on the outside heel and a little more wear on the inside toe. My left shoe (supinating foot) has extra wear on the outside midfoot. It's all starting to make sense. So, I'm sure right now that 99.7% of smart people will say, "You need to go to a doctor and have all this checked out." Well, maybe I'll get around to that sometime, but like I said, this is not a major issue, and I haven't experienced any injuries. I really don't feel any need to spend the cash and several afternoons going to different specialists just to eventually have some guy tell me, "Yep, your left leg is a little shorter," and give me a heel insert (orthotic for the fancy people). I really don't like running with heel inserts. It's uncomfortable, and I'm already used to years of running the way I am without injury. There is no way I would want an insert to fully make up the difference in my legs. I'm already an uncoordinated person to begin with; That's why I stuck with track instead of basketball in highschool -- following the line in a circle was easy! Since my body is used to compensating for it, I don't want to make any major changes. I would like, though, to try adding a little padding to my left shoe. Does anybody have good experiences with that kind of thing? Any recommendations? Perhaps just a pair of Dr. Scholl's gel thingys and throw away the right one? I guess I made this post way too long. I should've just said, "Hey, what do you use for a little extra padding in your shoes?"