I was diagnosed 3+ years ago with RA. Recently I started making my into tight fists while sleeping and often wake up with sleeping on them, which makes it even more painful, the pain eventually waking me. My hands are not that painful while I'm awake but I feel like I'm making things worse while I sleep. Is this common with RA? Should I try hand splints to keep my hands flat and in a more relaxed position while asleep?
One of the reasons that people with RA experience stiffness in the morning is because of the lack of movement that happens during sleep, so yes, it is normal for your joints to be more stiff and painful upon waking. There are a number of things you can do to decrease the pain. Splints may very well be a good idea for you - not only do they keep your joints in positions that keep them from curling in on themselves, they also offer support and protection should you e.g., lie on top of them. When you wake, you can put your hands in warm water and do gentle range of motion exercises until they "warm up". As well, decades ago while staying at a rehab hospital when I was a child, I learned this nifty trick: set your alarm clock to a couple of hours before you have to quit it up, take a painkiller (and a cracker or a couple bites of an apple, just to keep it company so it doesn't hurt your stomach) and go back to sleep. That means that when you wake, you're at the height of your painkiller's effectiveness and it makes it easy to get going in the morning.
That said, given that this problem with your hands is a recent development, I recommend you make an appointment to see you rheumatologist, just to check that everything's all right. When your body does new, weird things or develops new symptoms is always a good idea to run it by your doctor, just in case it's an early symptom of increased activity. It may not be, but better safe than sorry. While you're there, you can also ask for a referral to the physiotherapist who may be able to offer you some exercises that will help, as well as possibly try a hot paraffin wax treatment, where you dip your hands in warm paraffin (I believe also available at nail salons). It feels very good.