Body protectors are good for preventing the back pain 😋. I wear one every ride after I fell and fractured my spine.
Aleve works great. My doctor told me to take after a compression fracture in my spine from a fall!
I agree with Alyssa, hot baths always help and pain killers. Back pain after falling off really sucks especially when you try to get back on and can hardly walk your horse because your in so much pain! I've been there SO many times!
I used to fall off all the time when I first got the horse I have now. He was a chronic spooker. I found hot baths combined with extra strength Tylenol always did the trick for most of the pain.
Chiropractor first and then if your pain is only moderate then alternate heat and ice on the affected muscle and foam roll and if your pain is really bad I suggest acupuncture.