**Core Concept**
Pain of musculoskeletal origin refers to pain that arises from the musculoskeletal system, which includes muscles, tendons, ligaments, and bones. This type of pain can be caused by various factors such as injury, inflammation, or degenerative changes.

**Why the Correct Answer is Right**
Post-traumatic pain, as the name suggests, is typically associated with trauma or injury to the musculoskeletal system. However, post-traumatic pain is usually categorized as a type of neuropathic pain, which is pain caused by damage to the nervous system rather than the musculoskeletal system itself. This makes option C an exception to the list of pain of musculoskeletal origin.

**Why Each Wrong Option is Incorrect**
**Option A:** Myofascial pain dysfunction syndrome (MPDS) is a type of musculoskeletal pain that affects the muscles and connective tissue, causing pain and stiffness in the affected area.
**Option B:** Temporomandibular joint (TMJ) arthritis is a type of degenerative joint disease that affects the TMJ, leading to pain and limited mobility in the jaw.
**Option D:** Stylohyoid eagle's syndrome is a rare condition characterized by an elongated or calcified styloid process, which can cause pain and discomfort in the throat and ear.

**Clinical Pearl / High-Yield Fact**
It's essential to differentiate between musculoskeletal pain and neuropathic pain, as the treatment approaches differ significantly. Musculoskeletal pain is often managed with physical therapy, pain medications, and lifestyle modifications, whereas neuropathic pain requires more targeted treatment, including medications that specifically target the nervous system.

**✓ Correct Answer: C. Post-traumatic pain**