Final answer:
Pain from inflammation can stem from bradykinin and histamine release, which directly activate pain receptors, as well as from swelling that results in tissue pressure and potential nerve irritation.
Step-by-step explanation:
Pain accompanying the tissue reaction called inflammation may result from several factors, including bradykinin release, pressure from tissue exudate, histamine release, loss of function, direct nerve damage, and increased body temperature. When tissue injury occurs, various inflammatory chemical signals are released. Histamine, released by mast cells, causes vasodilation, leading to redness and heat. It also increases the permeability of local blood vessels, resulting in fluid leakage into the tissues, causing swelling (edema) and pain from the expansion of tissues putting pressure on nerve receptors. Bradykinin, another inflammatory mediator, directly stimulates pain receptors. Prostaglandins, synthesized by injured cells, also activate pain neurons. Both histamine and prostaglandins are involved in the onset of pain during the inflammatory process.