Who pays for pain and suffering when the person responsible for the car accident doesn't have enough insurance to even pay for your medical bills?

generally, it would be from your "uninsured/under-insured motorist" coverage. You wind up suing your own insurance company to collect. If the uninsured motorist coverage on your personal auto policy is not enough, you may also be able to tap the uninsured motorist coverage under your umbrella policy (if you have one). Now, if you live in a "no-fault" state you can tap the "personal injury protection" or something similar (different states call if different things). If you are in this situation, I'd highly suggest you consult an experienced lawyer.

AnswerYou would have to sue the responsible party in the accident for pain and suffering.

If they are insured for liability and you can prove pain and suffering in court, then their insurance company would pay a court judgement up to the policy limits.

If they are not insured for it then you would first have to pay your own lawyer expenses and you could get a judgement against the responsible driver with which you could then seek wage garnishments and property liens to recoup your loss.