Syphilis can be painful, depending on how far the infection has progressed. In its first stage, syphilis usually doesn't cause any pain - the only symptoms are small sores that are usually painless. In secondary syphilis, symptoms of syphilis may be more painful. These symptoms may include a sore throat and general soreness or weakness. Secondary syphilis can also cause painful sores that form in areas like the genitals, armpits, and mouth. By the time it reaches its third stage, syphilis can be very painful and can cause severe damage like heart failure, paralysis, and stroke.