Sudden sharp pain in the back

Over the last two or three weeks ive experienced a sudden sharp pain in my lower back about four or five times: each time ive collapsed to the ground – rendered completely unable to support my weight while it goes on; after around 30 seconds it dissapears, and i can get up and move around, no problem.

each time its happened when ive just been making a small, gentle move – like this morning, putting my socks on.

any thoughts, ideas on what the problem might be, or suggestions on how to treat it would be very much appreciated. cheers.