Recently, when i bend over (to pick up something), there is a lot of throbbing behind my eyes and temples. no pain and no sinus/allergy issues.

Sinus headache: There are many ways sinus issues can reveal themselves. Sometimes chronic sinus infections cause only post-nasal drip, a chronic cough, an A.M. Sore throat, or a low grade headache, all without nasal congestion or forward nasal discharge. The lack of classic symptoms often fools the best physicians. At times, only a cat scan will reveal the underlying problem. See a physician for an evaluation.