Yeah bro I hear ya!!!
Screw the 1, 4 Butananol and GHB advice cause that is not thw way to go. The 5-HTP or the Melatone (3mg) might be helpful but you are really talking about position here.
This is how I have been sleeping for the past 10 years thanks to working out and growing! ahahhaha
First, you will need to get at least 3 pillows. Put one firm pillow under your knees. When you lay on your back, always have it under there. When you roll over to your side at night, move the leg of the side that you are laying on under the pillow and your other leg over the top (so that the pillow is now between your knees. Grap a second pillow and put it between your elbows. (You can sleep with your arms out straight if you want. Try the pillow folded in half.) A third pillow will be under your head obviously. I use one of those buckwheat pillow under my head...they work great and I think that you can get them at walgreens or something like that. (They keep your head cooler at night and the give the best amount of support.) They are strange to sleep with at first but once you use them...you will NEVER go back to a regular pillow again!)
I hope that this helps...you can experiment however you see fit. It will take you a while to find your own "way" but once you do it will be easy and you will sleep much better.
Also...when I put on a lot of weight I will add a fourth pillow for when I sleep I may back....I put a pillow underd each arm...this keeps my arms from falling asleep.
I when from 5'5 118 to 195 lbs since Sr. year in high school...so I know that gaining size can really affect your sleep. When I am 175 I sleep much better at night.
sorry for the long post but I just wanted to help you out...let me know how it works out for you or if you have other question...
Good Luck,
Grainger!