Headache in back of head on left side when i cough. could it be aneurysm?

Symptoms of aneurysm: It is doubtful that your symptoms are related to an aneurysm. Aneurysm generally do not cause any pain or symptoms. It is more likely related to a cervical spine issue or a pinched nerve than an aneurysm.

Could be: Suspicion is first part of diagnosis for cerebral aneurysm, may manifest as mild head aches neck pains etc, see your physician will examine and refer to a specialist for tests, neglect may lead to tragedy.