There appears to be several words relating to this concept. One is Morgellon's Disease, a physical condition though its classification as a new illness is debateable.
Most doctors, including dermatologists and psychiatrists, regard Morgellons as a manifestation of known medical conditions, including delusional parasitosis The second, as mentioned in the above quote, is delusional parasitosis, which is a form of psychosis that results in the belief of crawling on / beneath the skin. However this sensation isn't always related to psychosis of course; the feeling itself is refered to as formication.
Sensation is the medical term meaning feeling.
Euphoria is the medical term meaning exaggerated feeling of well-being.
Anesth- is the medical terminology combining form meaning condition of not feeling.
Intoxication.
anesthiosisThe medical term for loss of sensation is anesthesia.anethesiaHSAN - which stands for Hereditary Sensory Autonomic Neuropathy. - This is the medical term for not feeling pain.
Palpation is the medical term meaning using the sense of touch to examine the patient.
Acid reflux
If it were a general state of feeling unwell a term often used is malaise. It doesn't specifically refer to a particular complaint, it is used for those who say they feel unwell.The medical term of generally feeling bad is malaise.Malaise is the medical term used to describe a general "run down" feeling.
Dysesthesia is the medical term meaning abnormal sensation.Dysesthesia is the medical term meaning a condition of abnormal sensation.
Nausea is the sensation that leads to the urge to vomit.Stomach achenausea
If you are talking about the feeling like you want to throw up, the term is nausea.
Rigors is the word for trembling due to feeling cold.