Hi, I'm at 18-year old male, 6'1" 152lb.  I lift weights often, I do cardio on occasion, and I eat pretty healthily.

When I'm going to sleep, I often find that my heart rate is often around 90bmp.  I also sometimes get kind of warm and sweaty when this happens.  This will happen even if I haven't eaten any decent amount of food within the past few hours before going to sleep.  My heart will also feel kind of uncomfortable, almost as if I want to "take it out of my body" because it's just creating discomfort, if that makes any sense.  I feel like I have to try to sleep in certain strange positions to minimize my heart discomfort, and I find that resting in a "twisted" position (for example, having my toes point into the bed but having the left part of my chest point away from the bed) often does this.  It's not a severe or sharp pain, just sort of annoying discomfort.

I probably get more than average hours of sleep per night (usually around 9.5 hours).  I've been having this discomfort when I go to sleep more often during the past few months, but I've loosely kept track of my heart rate during the past year, and it has seemed fairly high (especially relative to my age and level of fitness). I consume little to zero caffeine.  Also, my family doesn't have any history of any heart problems (or any other significant other relevant problems) that I'm aware of.  Can anybody provide some insight and advice about this?  Should I get even less sleep?  Eat even less food before I go to sleep (I have trouble gaining muscle as it is :P)?  Thanks 

EDIT: And actually, even when I'm not sleeping (but I'm just sitting), my heart rate is often ~88 bmp.