Lower back pain? You need to strengthen the core. Unfortunately squats, deadlifts, hyperextensions are NOT how you do that!
The fact that you have consistent lower back pain indicates your deep stabilizers (TVA, internal obliques, multifidus, pelvic floor muscles, diaphragm) are inhibited and not firing. Performing a traditional hyperextension in your state can increase pressure on the discs to dangerous levels and cause damage to spinal ligaments.
It'd be verging on impossible for me to go about explaining it without seeing you in person, so I highly suggest you find a good personal trainer. Continuing to deadlift when pain is caused will not help; it will only lead to potential injury.
-casual