Even though there are TCM treatments for "the painful scrotal mass", this is a red flag that needs immediate referral.
In ancient times there was no method to differentiate between the various causes, which include orchitis (inflammation of the testicle due to viral, bacterial or tuberculous infection), and epididymitis (inflammation of the epididymitis which often occurs with orchitis). Both are usually treated initially with antibiotics and observation over a week or two, unless the patient has clinical mumps, which is the most common viral cause.
The real reason, however, for the red flag is the possibility of incarcerated hernia or testicular torsion.
Most hernias are not painful. They can be uncomfortable if they are large, but they are not red, angry looking and extremely tender to touch. We are speaking of inguinal hernias here, a condition where the inguinal canal is open to the abdomen and allows bowel to descend into the scrotum. Most inguinal hernias slide back into the abdomen spontaneously when the patient lies down. Incarceration is a "pinching" off of the intestine somewhere between the abdomen and the scrotum. This causes a strangulation of the intestinal tissue and its supporting blood vessels. In this case the hernia does not go back into the abdomen, but instead becomes more swollen and can become necrotic (gangrenous) within a few hours. If not corrected surgically in a timely manner, the patient can develop sepsis (a blood infection) or the necrosis (dead tissue) that can spread to the attached bowel within the abdomen and cause peritonitis (a bacterial infection of the lining of the abdomen), both of which can result in death.
The other significant cause for immediate referral is the possibility of testicular torsion. As you probably remember, the fetal testicles descend from the abdomen through the inguinal canal and into the scrotum. They bring along with them their own circulation, both artery and vein. Sometimes in boys and young men the testicle twists, cutting off this blood supply and creating a very painful and swollen mass. If not corrected in few hours, the patient can lose the testicle. Although a person only needs one testicle to function, you do not want to be the health care provider that misses this. Not only is it highly litigious (keeping many lawyers in business), it is also just bad medical practice to miss it. Examination is difficult even for experienced professionals because of the associated pain. Often special tests must be done, such as ultrasound or nuclear scan to determine the exact cause of the pain. Again, an immediate referral might prevent loss of the testicle.
Finally, there is one painless mass that needs immediate referral, and that is testicular carcinoma. This is a cancerous nodule of the testicle that usually occurs in young men, and is often discovered by accident. Any nodule or asymmetrical growth of the testicle should be referred for evaluation.