Wayne, I tense up a lot when I sleep too -- in fact, not long ago, I began gritting my teeth and spent months thinking that I needed a root canal or something when really, it was my jaw that was aching. I'd also wake up feeling sore, especially my upper shoulders and thighs, as though I had I lifted weights the previous day. Like, you, I'd then be exhausted and achy. To my horror, it was discovered that I sleep walk at times (but this is not the only time I wake up sore) -- whether or not I wander around, sleep quite tensed up, or sleep beautifully depends upon how I begin the process of going to sleep. My best trick is to go to sleep listening to a meditation CD that focuses upon physical relaxation of the body. I have one called "Sacred Pool" -- it's one of several by Carolyn Conger, PhD & Michael Stearns, but if you just go to iTunes or your local New Age shop, you'll find plenty of others to choose from. I usually fall asleep towards the end of CD (30 mins) and I wake up refreshed. I was told by my dentist (of all people) that I probably go to bed with my stressful issues on my mind and fall asleep tensed up (true, because I stay busy all day and only at night do I have time to reflect).
Good luck to you -- this is something I have to consciously try to keep on top of. I have always LOVED sleeping; only recently has it been a source of trouble...you can see about going to a sleep center where they study your sleep patterns and such too, if you've got health insurance. I've heard that those sessions are insightful.