First question: why do you feel you need to sleep on your back? There is nothing wrong with sleeping on your stomach unless it's causing breathing issues or discomfort.
You could try a device used by people with positional sleep apnea. Generally they are used to keep people off their back but in this case it could be used on your front to keep you off your stomach. Check it out here
Sleep apnea has many bad effects on your body and mind. I found out I had sleep apnea. Before realizing this, I thought when I woke up super thirsty with my mouth dried out it was because I wasn't drinking enough water. Now I know it was from my airway being blocked and snoring and all the moisture getting sucked out of my mouth. I tried a C-PAPS device, but man, those things are terrible for me. Imagine having a constant stream of air being forced down your throat while you try to fall asleep! They do partially let up to let you breathe out, but not completely, so you never get to fully breathe out and your lungs are always overly inflated. Also, I was not able to use the device without lying on my back, and I'm not really able to fall asleep on my back, or rather it takes a few hours. I have a super long tongue and I think this contributes to my sleep apnea. I found out that I snore a lot more on my back and a lot less on my side and stomach, but especially on my side. I bought a nice mattress, not specifically nice for side sleeping, but it does make that a lot more comfortable for me (even though the reviews said it was bad for side sleeping, they were wrong). You can go to a Denver Mattress and try out different mattresses in the store until you find the one you like the most. They even have ones you think of as buying online. I also sleep with a knee pillow to make side sleeping more comfortable. My main issue with trying to sleep on my side is that as soon as I fall asleep, I roll over onto my back, which is strange because I'm not able to fall asleep on my back to begin with. It's as if my subconscious won't let me fall asleep on my back because it knows I won't be able to breathe, but then when I fall asleep that part of my subconscious goes to sleep too and I roll onto my back. In order to avoid rolling onto my back, I tried several different contraptions that aid in preventing this, all having varying levels of discomfort. The one I stuck with is not perfect, but it has the best balance of not being too uncomfortable and is relatively effective. It is these balls. They make it so that if you roll onto your back it will be uncomfortable and painful, thus preventing or training you not to do it. I found that over time I developed a tolerance for it, and I still had the tendency to roll onto my back after falling asleep. Now I use two of them on both sides of my back and place them higher up and this does the trick.