Bob, a 45-year-old graphic designer, is a weekend warrior an avid tennis player and gardener. He'd often spend his Saturdays serving aces and his Sundays tilling the soil. For the past two months, a nagging ache had been developing in his left shoulder, but he chalked it up to being out of shape. The pain was dull at first, a persistent throb after a long day of yard work. He could still lift objects, though reaching for something on a high shelf now felt like a chore.

Over time, the pain intensified. It began to interrupt his sleep, forcing him to toss and turn throughout the night. The simple act of putting on a jacket or reaching into the back seat of his car became a sharp, burning sensation. His tennis serve, once powerful and effortless, now felt weak and painful. Frustration mounted as he had to sit out games and abandon his beloved garden projects.