Pain only on the left side temple and left eye?

Probable headache. At 29 years of age it usually represents a tension headache. In an elderly individual a serious condition called temporal arteritis would be included in the differential diagnosis . Temporal arteritis can lead to blindness in the involved eye and is diagnosed by palpating a tender artery and an elevated sedimentation rate which is a blood tests. A temporal artery biopsy can confirm the diagnosis.
Pain temple and eye. We need more history before we can exactly tell you what it can be.It may be migraine, cluster headache or pain due to temporal arteritis.The questions to ask is if it is constant, or recurring or just one time pain.Do you have visual problems, if you get an aura, if bright light bothers you, does going to bed gives relief.Do you get nausea, is it related to alcohol intake or trigger by some other food.