[Dorufish]

I am a healthy man, doing sport at gym three times a week. I used to receive medications for blood pressure and cholesterol. Today my blood pressure and cholesterol are equilibrated. Lately my blood glucose increased a little (ca 110 mg/ml) as well as Hemoglobine H1c so that together with a weight decrease (5-7 kg) the doctor prescribed me Glucophage in a small dose.
Several years ago I happened to get headache in the left side of head and behind the left eye, after drinking alcohol-containing drinks (bear, wine). I stopped to drink any drink containing alcohol for a while and the phenomenon vanished. Later I have seen that even drinking did not trigger a headache.
Two months ago this phenomenon returned. As at the first time I stopped drinking any alcohol-containing drinks and the ache disappeared bu then it appeared again as a recurrent, similar (as above) headache, starting 2-3 hours after going to sleep. The ache was combined with a sensation of stiffnes of the neck. It passed, even without medication, after 30-45 min. Has anyone an idea what can generate this phenomenon?