ache和pain可能没啥差别，头疼和头好痛都对。从词典来看，有backache, bellyache, earache, headache, heartache, moustache/mustache (刮胡子时疼), panache (老公心疼……钱包), stomachache和toothache。有 [LDOCE]：
1. Her feet were aching from standing so long.
2. The pain in my jaw had come back.
3. He had a nasty pain in his leg.
4. If you suffer from back pain, consult your doctor before attempting this exercise.
5. The patient complained of severe chest pains.
6. She felt a sharp pain in her stomach.
7. I had a sore throat and aching limbs.
8. The astringent can cause irritation to sensitive skin.
9. You can use aches and pains to refer in a general way to any minor pains that you feel in your body.

[牛津] ache: continuous dull pain (持续而隐约的)疼痛。止痛药: painkiller。也许pain更painful些，毕竟achy长得像itchy, scratchy: 史羊羊。pain <= Old French <= Greek (payment, punishment). 近义词: agony, discomfort, distress, hurt, irritation, pang, soreness, torment.
sore: hurting when touched or used; tender and painful; aching (指身体局部) 一触或一用就痛的。

ache可以作动词，接介词不头疼。for/with，也可以接不定式，比喻的说法。anguish很疼了: mental or physical suffering caused by extreme pain or worry. 找不到比denounce (express strong disapproval)更强烈的词的话，也许只好express extremely strong disapproval indeed了？

[柯林斯]
a. If you say that you are hurting, you mean that you are experiencing emotional pain.
I am lonely and I am hurting.
b. The sun's hurting my eyes.
c. The day was bitterly cold.
d. The house felt cold and empty.
e. My tea's gone cold.
f. I'm cold.

"Strictly speaking, there are some differences between the two words. The word 'ache' is used to refer to a kind of discomfort in some part of the body. On the other hand, the word 'pain refers to acute discomfort." The point is, 背acute这个单词。

Migraine is a primary headache disorder characterized by recurrent headaches that are moderate to severe. Typically, the headaches affect one half of the head, are pulsating in nature, and last from two to 72 hours. Associated symptoms may include nausea, vomiting, and sensitivity to light, sound, or smell. The pain is generally made worse by physical activity.] Up to one-third of people have an aura: typically a short period of visual disturbance which signals that the headache will soon occur. Occasionally, an aura can occur with little or no headache following it.

Migraines are believed to be due to a mixture of environmental and genetic factors. About two-thirds of cases run in families. Changing hormone levels may also play a role, as migraines affect slightly more boys than girls before puberty and two to three times more women than men. The risk of migraines usually decreases during pregnancy. The underlying mechanisms are not fully known. It is, however, believed to involve the nerves and blood vessels of the brain.

六级/考研单词: ache, jaw, nasty, consult, limb, irritate, perpetual, punish, distress, tender, anguish, physics, denounce, disapprove, lonely, strict, differentiate, acute, moderate, affection, symptom, disturb, decrease, pregnant, underlie, vessel

Sheldon: I have pain radiating from my navel to my lower right abdomen. I'm nauseated and feverish. I believe I may have cholera.

Leonard: There's no cholera in Pasadena. Just like last summer, when there was no malaria in Pasadena.