I suffer with lower back pain and shouting pain in left leg. For the last few weeks my legs have given way on me they become heavy and sore and don't?

Nerve damage? A pinched nerve in lower spine that's radiating down leg, following the nerve .This is Sciatica,+ usually follows episode in past for low back pain. It could be Herniated Disc pressing on nerve Recommend lying down on back with knees propped up on pillows, ice or warm compresses to area see if it relieves pressure on nerve. No heavy lifting. If no better, need to see doctor. Take Advil (ibuprofen) .