Today lamp fell on my head from the top shelf. it's a wooden lamp and quite hard. i have a sore head and it aches every so often. is it safe to sleep?

Concussion: Or epidural hematoma? Impossible to tell without physical, neurologic examination and appropriate imaging (ct, mri) head trauma should not be taken lightly. Symptoms of a head injury may occur immediately or develop slowly over several hours, days or months. For a mild head injury, no treatment may be needed, but visit to pcp is warranted. Take care.

Ouch: If not unconscious, likely just bruised- contusion. Ice and rest and time will take care. If more then concussion is possible.