Yikes! That doesn't sound very fun! How long has it been going on? Do you think he could be teething? Is he a bit sick?
What happens if you don't pat him? Does he cry and cry and cry? If you pick him up is he ok?
I'm sure it will get shorter. I tend to leave Flynn to whinge a bit and if it escalates I give him a cuddle and then put him down again. I usually only have to do it once or twice and he is gone.
As for tummy sleeping, I wouldn't worry about it. Flynn is the same, he favours side or tummy more than his back.