Yes, you will need a wheel alignment after lifting your truck. Lifting a truck changes the geometry of the suspension, which can cause the wheels to be out of alignment. This can lead to premature tire wear, poor handling, and decreased fuel efficiency. A wheel alignment corrects the angles of the wheels so that they are perpendicular to the ground and parallel to each other. This will help to extend the life of your tires, improve handling, and increase fuel efficiency.
It is important to note that a wheel alignment should be performed by a qualified technician who has the proper tools and equipment. If you are not comfortable performing this task yourself, you should take your truck to a reputable auto repair shop.