Friend hit me in the head. not hard,more like a joke. could that cause a concussion or brain bleed?

No: While in medicine, anything is possible and of course it is possible, it seems exceedingly unlikely to the point of impossible and certainly improbable. Do you have any symptoms? Loss of consciousness? Headache? Difficulty thinking or concentrating? Nausea? Vomiting? If you have none of these sympoms, the answer remains no. If you do have them within 6 hours, perhaps get checked out.

Not likely: 27 year olds rarely suffer concussions or bleeding from slight trauma. If you are not having any symptoms like headache, dizziness, trouble walking, or nausea, no need to worry.

Unlikely: It does take certain momentum and force to cause concussion. Brain bleed take even more trauma than trivial hits. Loss of consciousness often is associated with significant concussion.