I want to know how to calculate pain and suffering for a car accident small claims lawsuit?

It was not advisable to file a personal injury lawsuit in Small Claims Court because the amount you recover will be limited. The case should have been filed in Superior Court. Unless the statute of limitations is rapidly approaching, the lawsuit should not have been filed until you completed your medical treatment because you wouldn't know the total bills, wouldn't have the final medical report, and you won't be able to go back later and seek additional compensation for further medical treatment.  If the insurance company is not paying for the medical treatment, you can continue medical treatment if you find a doctor willing to take the case on a lien basis.  This means the doctor is paid out of the settlement of the case.  When you complete your medical treatment and are released by the doctor or are declared by the doctor to be permanent and stationary, which means having reached a point in your medical treatment where no further improvement is anticipated, obtain your medical bills, medical reports and documentation of any wage loss.  Your personal injury claim filed with the other driver's insurance carrier would include these items.  Compensation for the medical bills is straight reimbursement.  Compensation for wage loss is straight reimbursement.  The medical reports will document the nature and extent of your injury and will be used to determine compensation for pain and suffering, which is an amount in addition to the medical bills.

As for computing pain and suffering, there isn't any mathematical formula.  It just depends on the facts of the case.  For example, if after completing medical treatment, you have residual complaints such as pain or other problems, that would mean additional compensation for pain and suffering compared to someone who did not have residual complaints.  Also, if the medical report states that you will need future treatment, the estimated cost of that future treatment discounted to present value should be included in your settlement.

I would usually ask for quadruple the medical bills to compensate for pain and suffering, but not expecting to get that.  That would be a starting point in negotiations with the insurance carrier.  The insurance carrier will respond with a much lower offer and then try to get them to increase their offer.  If you are dissatisfied with settlement offers from the insurance carrier, reject the settlement offers and file your lawsuit for negligence against the at-fault party.  If the case is settled with the insurance carrier, NO lawsuit is filed.  If the case is NOT settled with the at-fault party's insurance carrier, you will need to file your lawsuit for negligence against the at-fault party/registered owner of the vehicle if different than the driver, prior to the expiration of the applicable statute of limitations or you will lose your rights forever in the matter.

Another problem is that attorney who dropped your case will assert a lien to be paid out of the settlement of your case.  The settlement has to be sufficient to pay that attorney, pay medical bills and compensate you for medical bills, pain and suffering and wage loss.