I know that viruses and sharp forces can stimulate mast cells by cut or by a virus infecting them and then release histamine. How can blunt force do this and cause inflammation? It doesn't have the above process. And how will the macrophages, neutrophils and plasma cells react to this type of inflammation when there is no bacteria or viruses to swallow and create antibodies for?
An brunt force (trauma) may destroy cells and tissues by mechanical action. It simply squashes them.
Cells contain different kinds of chemical substances in specific cellular organelles. The most important in this context are enzymes from lysozyme.
Once enzymes are released (by squashing the cell) they induce irritating reactions to other cells and activate specific receptors found on immunitary system cells. This is how non-infectious inflammation occurs.
Cell components act as inflammatory mediators responsible for the clinical signs of inflammation. Here are some examples [Wikipedia]:
Other inflammatory mediators are produced by macrophages, neutrophiles and plasma cells, thus leading to a chain reaction, in which immunitary system cells activate one by another.
Macrophages have enough to 'swallow': all the destroyed cells which must be removed from the tissue.
Antibodies are produced because altered cell structures are considered non-self and gain antigen properties.
Source: Wikipedia, Inflammation