My immediate thought is "Did you hit anything whilst convulsing?" Perhaps you hit your ribcage on the corner of a dresser. Was there anyone else around who can tell you? I had a sz once and I had similar feelings. It turned out that I had hit the washing machine. Te only other thing I can suggest is talking to your doctor. It may be that he/she has some answers.
As for back breaking sz's... I suppose a jerking action could break someones back but me thinks that you would need a lot of jerk!
Hope this helps and welcome to HealingWell!
5 weeks does sound like a long time to be suffering from the pain in your ribs and back. An X-Ray sounds like the best course of action. Your GP might be able to suggest other treatments for you (Such as Physiotherapy) to get you back to your old self. It might be worth asking what caused it in the first place and if there are any ways to avoid it happening again. Let us know how you get on.
I agree with Paul. Anything up to a week after a major sz with muscle pain can be normal. I also like your analogy Paul. I used to tell people it was like going 10 rounds with Mike Tyson. (A famous boxer if you have not heard of him).
Let us know how you get on Whitney.