Why am I itching for no apparent reason? My left arm and shoulder show no signs of a rash but I itch terribly and it hurts. It feels like somebody is sticking me with a pin. It is not continuous but I usually have this problem 2-3 times daily especially

Itching. If it is localized itching, it can be a neuropathy, do you suffer from neck pain? You may have a pinched nerve. Another cause if cardiac, but that is ore heaviness and pain than itching, you mentioned your arm hurts, i think it is time to have a check up with your doctor.
Itching . Itching with no signs of a rash is something that many people experience, however it does require evaluation by a doctor. The itching can be related to: 1. An early sign of infection 2. Skin infestation such as scabies 3.Medication induced 4. Food induced 5. Other medical conditions such as kidney failure, hormonal imbalance, liver function issues which cause itching around the body as a side effect\ since the etiology is unknown, it will be crucial for your doctor to investigate.