DEAR DR. DONOHUE: I have an aching pain in my shoulder. The doctor doesn’t want me to quit playing tennis, but it is painful. She said, “When you don’t use things, they weaken.” Is there a name for my condition? Is it something I must live with? – S.G.

ANSWER: It’s true that if you don’t use it, you lose it. It’s also true that if you don’t move the shoulder at all, it can freeze – move only with great effort and pain. However, it’s also true that pain is a sign that something is wrong, and to ignore it can make matters worse.

You might have tendinitis or bursitis – inflammation of the tendons that run over the shoulder and hold the joint in place, or of the bursa that permits the tendons to glide over bones without creating friction. Both cause pain when you lift your elbow upward and outward to the side of the body. Rest, but not immobilization, is essential for healing. Anti-inflammatory drugs like ibuprofen can ease the pain and lessen inflammation. Moist-hot compresses also help. If heat isn’t working, try an ice pack. Keep the shoulder mobile by bending over at the waist and making circles with the dangling arm and hand – if it doesn’t hurt.

Impingement syndrome is another possibility. It’s the rubbing of shoulder muscles, tendons or bursa against the shoulder blade part of the shoulder. It makes lifting the arm up high painful – the motion of serving a tennis ball. The above routine works for it too.

A tear of the rotator cuff is a third possibility. It causes pain when lifting the arm over the head, and its pain often worsens at night. Rest is important here. If healing doesn’t take place, surgery might be necessary. You need an accurate diagnosis with specific instructions for your shoulder problem. You should make an appointment with an orthopedic surgeon.

DEAR DR. DONOHUE: I am a 37-year-old man and weigh 160 pounds. I want to build my muscle mass by about 20 pounds. I lift weights every other night, and I jog every day. What nutritional protein supplement will help me? – M.C.

ANSWER: Since muscle is protein, it’s only natural to think that increasing the amount of protein in the diet will build muscles. However, most of us get far more than the recommended daily amount of protein, which is .36 grams per pound of body weight (.8 grams/kg). A person who weighs 155 pounds needs only 56 grams of protein a day. That’s not a large amount. Three ounces of ground beef has 25 grams, and a 3-ounce portion is pretty small.

For a person who’s exercising very hard, the protein requirement is double that of the average person. Even so, that’s still not a great amount, and most of us get that much in our diet without trying. If you want to try a protein supplement, go ahead. It won’t hurt you. Protein supplements are often sold as amino acid supplements. Amino acids are the basic units of proteins. There is some evidence that eating protein an hour after exercise increases the body’s synthesis of protein and, therefore, muscle. That’s a stratagem to try to increase muscle mass.

DEAR DR. DONOHUE: A friend and I began an exercise program about a week ago. He’s very competitive. I can do more sit-ups than he can, and that really pulls his chain. The other day, he went home after we exercised, and his wife told me he did two hours of sit-ups. The next day he was in such pain that she took him to the hospital, and he was admitted. They told her his muscles had broken down, and they were afraid his kidneys might shut down. What happened? – R.C.

ANSWER: He had exertional rhabdomyolysis. The excessive amount of exercise damaged his muscle fibers, and they released myoglobin, a protein in muscles that helps them use oxygen. Myoglobin turns the urine tea-colored. It can settle out in kidneys and destroy them. Your friend definitely went overboard.

DEAR DR. DONOHUE: Our 26-year-old son has had severe tonsillitis off and on for the past four years. He misses a lot of work. The doctor doesn’t want to remove his tonsils. Why not? Our son is going to lose his job if this keeps up. – C.H.

ANSWER: Because recurrent tonsil infections in adults are most often due to the strep germ and because such infections usually respond to antibiotics, adult tonsillectomy is not common. But there are no hard-and-fast rules forbidding it. If an adult has three or more tonsil infections a year, surgery is considered. If an adult has more than four, tonsillectomy is generally recommended. Your son should seek a second opinion.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.