Proctalgia, and Sundry other Pains

aerodontalgia - toothache caused by atmospheric decompression (for example in high altitude flying).
arthralgia - pain in one or more joints.
cardialgia - (1) heartburn; (2) pain in the heart.
causalgia - constant burning pain due to peripheral nerve damage.
cephalalgia - headache.
cephalgia - headache.
coxalgia - pain in the hip.
cranialgia - pain occurring within the skull; headache.
enteralgia - pain in the intestines.
erythromelalgia - hot skin rash with burning pain. Usually in the feet.
fibromyalgia - chronic widespread pain with tenderness and muscle stiffness.
gastralgia - pain in the stomach.
hypalgia - hypalgesia, i.e. diminished sensitivity to pain.
ischalgia - pain in the hip.
mastalgia - mastodynia, i.e. pain in the breast. Not often observed in men.
meralgia - pain in the thigh.
metatarsalgia - burning pain below and between the metatarsals where they join the toe bones.
myalgia - pain in one or more muscles.
nephralgia - pain in a kidney.
neuralgia - acute, paroxysmal pain along one or more undamaged nerves.
nostalgia - homesickness; sentimental yearning for the past.
odontalgia - toothache.
otalgia - earache.
polyarthralgia - pain in two or more joints.
polymyalgia - myalgia affecting several muscle groups.
proctalgia - sharp pain of the kind caused by blog posts like this.
psychalgia - mental distress.
veisalgia - sober medical term for a hangover.

Sources: Merriam-Webster OnLine, MedicineNet.com