@Crispety - I didn’t know that you could get lower back pain from running. It makes sense if your posture is off.
I just wanted to add that the last time I felt lower back pain and cramps was when I was pregnant. I was getting back cramps during the end of my pregnancy and at first I didn’t know that I was getting close to going into labor.
The pain was awful but it only lasted for a minute or so and then it would completely go away. When I started to get close to going into labor the frequency of these painful intervals would increase.
I just tried to do my deep breathing exercises until the pain went away. The hardest thing about this back cramping is that you can’t sleep because it continues to come back. I remember when I went to the hospital because of my back labor, they gave me some sleep medication because the pain was getting stronger and stronger and I was not even close to giving birth.