Employee got into the back of a pick up bed to fix an issue with a buggy whip, as EE stood up from a crouched position EE lost bearings, got light headed and took some steps backwards and misjudged the end of the pick up bed, fell on back and hit head. EE was checked by a Supervisor, refused medical treatment. On 07/09/2020 Employee went to ER, taken off work one day.