Hit my head very hard on friday and today there is still a little painful bump in that area is it dangerous?

Probably not . Concussions can result from what can seem like a mild impact to the head, even if there are no symptoms immediately. Head injury followed by any headaches, nausea, vomiting, dizziness, or other neurologic symptoms needs immediate attention but longer term less dramatic symptoms such as trouble with mood, concentration, sleep can also be the result even with a normal ct or mri.
Head injury. There are several red flags that could mean there is something more serious then a bruise or soft tissue injury. These include worsening or constant headache, loss of consciousness , intractable vomiting, any neurologic symptoms such as numbness weakness or vision changes. Only having mild swelling and pain at site is probably normal.
Probably not. If you are fully conscious and have no neurological symptoms you are likeely ok. If there is any question, get it checked out.