Is a combination of meds like tramadol, amitriptyline and zoloft (sertraline) better for controlling nerve pain than one of the meds alone ?

Depends: Presumably you're working with a neurologist or pain management specialist for neuropathic pain treatment. If not, you should see one. It is always better to treat a condition with the least number of medications and the lowest dose of each medication possible. Discuss this with your physician. http://www.webmd.com/pain-management/guide/neuropathic-pain