Thank you for sharing your problem - back pain can be a real concern and having experienced it before I fully empathise!
Did the pain come on suddenly and was there any pain that travelled into your leg?
What was the nature of your pain? Pain with flexion is often associated with a discogenic, cause and it doesn’t always require there to be radicular (nerve-related) pain.
Localised pain may be due to a facet joint or area of increased muscle tone - depending on where the pain localises to.
For most back pains, symptoms will resolve with offloading, analgesia and good rehabilitation. In situations where pain is ongoing or where you have worrying symptoms, further investigation may be warranted.
Perhaps you could start with rehabilitation for your back with a physiotherapist, offloading from the aggravating activity and looking at a running gait analysis to investigate whether your symptoms are arising from your running form.
Good luck with your symptoms and running - please do contact us if you have further questions.
Bw
Dr Dinesh