hopefulbutt, spams can be very intense when the fissure is fresh and active, some people feel the pain different and it progress into stages as it starts to heal.
I used to feel pain in my entire anal and vaginal region when having spams, mine lasted day and night, I spend many nights just crying in pain because it was not position I could lie to find relief.
But something that help me with the pain was
massaging the area where the pain was the worst, usually next to the skin tag where the fissure is located, also I used to do pelvic floor exercises to keep the bladder strong but I found out that doing the opposite rather than holding the muscle but trying to release the muscle like going into a BM did wonders for me and finally I was able to sleep at night again.
Some people will
seat on a heating pad to help release the muscle also when is too tightIs a lot of trial and error while dealing with a fissure as not every one feel the same, (beside the agonizing pain of the spams), because we all experience pain different.
You can try either massaging the area gently or doing pelvis floor exercises and see if it works for you.
I hope things get better for you.