Do you recall any recent injuries to your back, that may be causing you to have intermittent cases of pain? Is there some lifting or activity your doing on certain days that might be putting strain on your back, joints, and legs? I would really review your daily activities and consider what might be causing this intermittent pain, because chances are something is contributing to it.
You could try alternating ice and heat 15-20 minute intervals each - the ice will help reduce the inflammation and the heat will help to relax your back and hopefully help to alleviate any spams that might be occurring.
If the pain continues I would recommend you consult your Doctor.
I hope you get answers and relief soon.
~ Fiona Jo ~