Oh Chris - I'm so sorry - I really commiserate with you. Back pain is AWFUL!
Just do what you know is best - do you have a decent pain killer to take? I always find cups of tea and a cat on the knee just about the best thing!!
Oh I know that shuffle-walk too - Don says I look like my knickers are falling down!!!
Take good care of yourself and I hope it's only a spasm and will pass very soon. xxx

Lynne