Algophobia is an intense, disruptive, and irrational fear of pain or extreme discomfort. Everyone fears pain to some degree - this is a good thing that is a very beneficial quality to have. But algophobics have irrational and hypersensitive fears that make them unable to perform normal tasks.
Examples are avoidance of movement or moving things (for fear of injury), workplace fears (such as being injured by equipment or tools), or social interactions (like sports or activity for fear of being injured). Their fears of pain or discomfort disrupt and inhibit algophobics lives and don't allow them to live normally. Algophobia sometimes is a result of experiencing a traumatic event.
For an algophobic, when faced with a normal situation that might be painful or discomforting (a dental checkup for example) they experience anxiety symptoms such as increased heart rate, breathing issues, shaking, panic, and avoidance. Behavioral therapy has been shown to be highly effective in the treatment of algophobia.