**Core Concept**
Fibromyalgia is a chronic condition characterized by widespread musculoskeletal pain, fatigue, and tender points. The pathophysiology involves central sensitization, leading to an amplified pain response to stimuli.

**Why the Correct Answer is Right**
The correct answer is based on the diagnosis of fibromyalgia, which is supported by the patient's symptoms, physical examination, and normal laboratory findings. The tender points over the neck, shoulders, elbows, and wrists are characteristic of fibromyalgia. The absence of joint swelling or deformity, normal complete blood count, and negative rheumatoid factor also support this diagnosis. Treatment of fibromyalgia typically involves medications that target pain modulation and sleep disturbances.

**Why Each Wrong Option is Incorrect**
**Option A:** Medications such as corticosteroids and NSAIDs may provide temporary relief but do not address the underlying pathophysiology of fibromyalgia.
**Option B:** Physical therapy and exercise may be beneficial for patients with fibromyalgia but are not the primary therapeutic option.
**Option C:** Antidepressants, such as amitriptyline, are often used to treat fibromyalgia due to their ability to modulate pain and improve sleep.

**Clinical Pearl / High-Yield Fact**
Fibromyalgia is a diagnosis of exclusion, and a thorough evaluation should be conducted to rule out other conditions that may mimic its symptoms. A tender point examination can be used to support the diagnosis, but it is not a definitive diagnostic tool.

**Correct Answer:** C. Amitriptyline is a tricyclic antidepressant commonly used to treat fibromyalgia due to its ability to modulate pain and improve sleep.