Gethigh- the most important thing is to be open with your doctor and if they are unresponsive and don't deliver than find a new doctor.
IME w/ doctors, they don't like it a lot of times when you try to recommend things so I wouldn't straight up ask him for the pump. There are various ways to discuss it with him... 1.) You could tell him that the current regimen is insufficient and you need to make changes to better control your pain 2.) You could mention reading about the intrathecal pumps and ask him what he thinks about it, etc.
My main point is that its important that your doctor feel like he is in the driver's seat of the treatment. At the same time, he can only make informed decisions if you are open with him. You need to tell him how miserable you are and what you want and need out of treatment so he can understand what needs to be done.
From what I know, those pumps are generally reserved for when people max out other options- i.e. are on such a high dose of oral opioids that its no longer feasible to continue via that route. I am not sure on your current meds if a doctor would consider a pump unless it was more for a local anesthetic or something non-narcotic.
I understand how horrible it is living with uncontrolled pain and that is why its sooo important that you get a doctor that you can be open with and who is responsive to your needs. If your doctor is pulling the "I know best (live with your pain)" bullshit, than you need to move on. If your doctor will listen, then express your desperation in the most colorful language that you can. Most doctors if you communicate how shitty this is making your life, will feel a sense of obligation to better control your pain.
I hope some of this helped and feel free to ask any other questions here or in PM, I have been through all the BS with about 2 dozen doctors and I'd love to share any insight that might be helpful. You need to find pain relief and you need to push until you get it, no one is going to for you and you need to be able to live your life relatively pain-free. Best of luck!