Got rear-ended last week. The other guy's insurance called me today and said they'd cover the body shop estimate and give me $500 for 'pain and suffering'. But they sent over a release waiver I have to sign first. My neck is still a little stiff but I don't think it's major. Should I sign this or talk to a lawyer first? I don't want to get screwed if my neck gets worse later, but I also don't want to drag this out if it's a fair offer.