I've known many people with chronic pain -- and the danger of becoming addicted to pain medicine is very real for someone like you. And the longer you let this continue the greater the danger becomes.
But you shouldn't be afraid to share your concern with your doctor -- and I urge you to do so as soon as possible. I'm not a physician, of course, but your doctor knows your situation, and may suggest other pain medicines (or lower doses of your present medicine). Don't let your fears keep you from getting the best medical advice you possibly can.
But the most important thing I can tell you is that God knows what you're going through, and He loves you and wants to encourage and help you. Do you remember Job in the Old Testament? He endured almost unimaginable pain -- but in the midst of it he discovered that God was still with him, and he learned to trust the future into His hands. Job declared, "Though he slay me, yet will I hope in him" (Job 13:15). His pain helped him see what's really important in life -- and that is our relationship to God.
May this be true of you. If you have never done so, turn to Jesus Christ and ask Him to come into your life today. Then thank Him for being with you even when life is hard. His promise is true: Nothing "will be able to separate us from the love of God that is in Christ Jesus our Lord" (Romans 8:39).