I've noticed a difference in my lifts as far as targeting the pec area better when i arch my back a little bit and poke my chest upwards rather than keeping my back flat against the bench? Everytime i keep my back flat against the bench, especially on incline for chest i hit my shoulders? And i probably have the bench even less than 45 degrees for incline
Yes this is the correct form for bench pressing. The arch "poking" the chest upwards promotes the setting of the shoulders firmly into the bench and the contraction of the scapular, giving you a solid base to press from. This lessen the shoulder movement, thus less involvement in the lift.
Another thing to try is to crush the bar together in your grip. This way you are activating the chest more than the triceps.