I have terrible pain to the point where sometimes i cant keep wicket twice in a weekend.
Its caused by a bulging disc (not slipped) and there isnt a lot that can be done for me other than surgery to fuse my vertebrae.
I would hope your case isnt as serious, i will give you some tips than have helped me to ease the pain to manageable levels.
Stretch your hamstrings! Not just before exercise, do it 2-3 times a day, tight hammies are a major cause of a bad lower back.
Also, try some resistance bands. Lay on your side and wrap a band round both ankles, lift your top leg as high as possible and hold for as long as possiblem repeat until kanckered. Then do the same but with the band around your knees, then your thighs. This helps build strength around the sore area.
Most important, lose weight (this is my big issue....)
Good luck