I work a hard factory job, and my knees have been hurting, what should I do?

for the last couple months my knees have now started to hurt. I had hurt my back, so I had to continue working while relying mostly on my knees, and now my knees have started to ache. I started a new job there, without much heavy lifting, but lots of walking in a circle. My knees still hurt some, but not sure if I should just never mind it, or if I should be weary that I could damage them permanently?