I experienced this the weekend before last, after lots of big jumps. Since I have been taking glucosamine with chondroitin and msm, the back vertabrae soreness eased up pretty fast, especially with the help of a "heat belt" from wal mart, kind of like a kidney belt. Charcoal activated, stays warm about 12+ hours. It really helped with the soft tissue soreness too. I used to take ibuprofen but have heard some bad things about the long term effects, so I just try to tough it out. I agree it will get better as your body adapts after some more track riding. Weight training should help too. I guess I should take my own advice on that... :)