Ya funciona, Aquí las correcciones:
Código PHP:
SELECT Repricing.ConvertedProfessionalCharges as pprofessional, Repricing.ConvertedHospitalCharges as phospital,
Repricing.ConvertedTotalCharges as ptotal,
SUM(ClaimsFollowUp.AmountReceived) as Total_Recibido
FROM Repricing, ClaimsFollowUp WHERE
Repricing.RepricingID=930 AND ClaimsFollowUp.RepricingID=930
GROUP BY ConvertedProfessionalCharges, ConvertedHospitalCharges, ConvertedTotalCharges
Saludos y Gracias