The pilot stated that in preparation for a night flight, he flew earlier that same evening. He inspected the airplane and noted the control lock was not installed in the control column. While searching for the control lock he located a “straight pin” in a seatback pocket and installed it. He left the airport and returned later than evening, and performed a preflight inspection of the airplane removing the straight pin. He departed and flew to his destination airport where he landed uneventfully. After landing he went to a fixed base operator and filed a flight plan for the return flight, then returned to the airplane and started the engine. He taxied to the run-up area of runway 34 where he performed the before takeoff checklist but did not check that the flight controls were free and clear for fear of having his tablet knocked off the yoke mount. He advised the controller that he was ready for departure and was cleared for takeoff. He taxied onto the runway and applied power noting the airspeed increased normally. After the airplane rotated it climbed to an altitude of about 3 feet and settled back down on the runway and bounced. Confused as to what was occurring, he added nose up trim to assist in the climb. At this point the airplane climbed to about 10 feet, then the nose pitched downward and the nose wheel struck the runway. After coming to a stop he switched the headlamp he was wearing from red to white and noticed the pin used to secure the flight controls was in the control lock hole. He removed the pin and retained possession of it. Post accident inspection of the airplane by a FAA inspector revealed substantial damage to the firewall.