My kidneys hurt in that sort of area when I get jostled, even bouncing in the car through construction, etc. I have polycystic kidneys, though, so much larger than normal. My nephrologist didn't get it when I was first seen, but the MRI helped him understand it was related. My pain is generally in that range of the pain scale. A heating pad and rest helps me most of the time, unless I was also passing a kidney stone, lol!
Do you wear a "kidney belt" when riding?
(One of my brothers used to wear one as a kid when trying to race motorcycles. His kidneys still couldn't take it cysts broke and bled a lot, so he had to give that up. Just a thought that popped into my head.)
Since you don't have PKD, I hope it's not your kidneys