"Will I ever be able to sit comfortably?"
It depends in part on your willingness to sit through "uncomfortable."
It also helps, if you are sitting on the floor, to use just enough cushion to keep your hips higher than your knees, thus relieving pressure on the lower back. Many westerners who did not grow up sitting on the floor need some slight elevation. If you can, wean yourself off any kind of backrest asap. If you are sitting on a chair, sit forward on the seat.
My initial meditation practice began at home, on a buckwheat hull zafu and zabuton, no back support from the very beginning. After a series of 5 full weekend sessions (a continuing course), the basic position was more or less "comfortable." Continuing that practice, my position evolved into half lotus relatively easily. Back pain is also exacerbated by weak abdominal muscles, so some emphasis on exercise in that area was also helpful. Also, lots of yoga helped with flexibility.
I would say it took 2-3 years of daily practice to be able to sit for an hour feeling completely "comfortable."
Just do your best, stick with it, and best wishes.