Multiple Sclerosis (MS): A chronic autoimmune disease that affects the central nervous system, leading to a wide range of neurological symptoms, including paresthesia (abnormal sensations like pin-pricks). The pin-like feeling on one side of the body could be an initial presentation or a relapse of MS.

Peripheral Neuropathy: Damage to the peripheral nerves can cause numbness, tingling, or a pin-like feeling, often on one side of the body. This could be due to various factors such as diabetes, vitamin deficiencies, or trauma.
Radial Neuropathy or Ulnar Neuropathy: Compression or damage to the radial or ulnar nerves can cause paresthesia on the affected side, typically in the arm or hand.
Stroke or Transient Ischemic Attack (TIA): Although less common for a pin-like feeling to be the sole symptom, it's possible for early or mild strokes to present with transient or mild sensory symptoms.

Spinal Cord Compression: Compression of the spinal cord can lead to a range of neurological symptoms, including paresthesia. This is a medical emergency requiring prompt intervention.
Acute Stroke: While mentioned earlier, it's crucial to reiterate that any new neurological symptom, including a pin-like feeling, warrants immediate evaluation for stroke, given the potential for severe outcomes if not promptly treated.
Multiple Myeloma: A type of blood cancer that can cause peripheral neuropathy among other symptoms, including bone pain and anemia.

Sjögren's Syndrome: An autoimmune disorder that can cause peripheral neuropathy, among other symptoms like dry eyes and mouth.
Vitamin B12 Deficiency: Can lead to neurological symptoms, including paresthesia, due to its crucial role in the synthesis of myelin.
Lyme Disease: In its later stages, Lyme disease can cause neurological symptoms, including neuropathy and paresthesia, though this is less common.
Sarcoidosis: A condition where inflammatory cells form in various parts of the body, potentially affecting nerves and causing neuropathic symptoms.