Painful, sore, red gums can be a symptom of gingivitis (inflammation of the gums) or, more likely, periodontitis (inflammation of the attachment fibers of the teeth and supporting bone), which can arise due to a number of different causes.
klick (plural klicks) ( 1 slang, military) A kilometer. 2002, Robert J. Sawyer, Hominids an asteroid between one and three kilometers wide had slammed into the ground at fifteen klicks per second. ( 2 slang, usually in the plural) Kilometres per hour.
It is just another name for military job. In the Marine Corps, the MOS is a four digit number that represents the kind of job you are assigned. The first two digits are the category of your job, and the last two digits are the specific job title. So for a MOS of 0331, the 03 means that you are Infantry, and the 31 means you are a machine gunner.