Wanting to take off your bra as soon as you get home or being stabbed in the underarm is a clear indication that you are not wearing the right bra FOR YOU, regardless of what a fitter says.
Finding the right bra isn't easy--much like finding the perfect pair of jeans. What works for one person can be way off for another because our shapes and preferences vary so widely. A good fitter can guide you to sizes and styles that might work, but only you can judge how a bra actually feels when it's on your body. Cup design and seaming; underwire length, gauge and shape; gore attachment and shape; fabrics and linings; strap placement; and band construction are just as important as size when it comes to comfort.
My suggestion would be to have a fitting at several bra boutiques before purchasing another bra. Trying on a wide assortment of styles and brands at a variety of pricepoints is the only way you can identify the features and styles that work best for you. A good fitter will understand why you want to do this before buying another bra. Most shops only carry half a dozen brands--and it's entirely possible that the best bra for you just doesn't exist in their selection.
And, can I say, it's important to let go of any prejudices you might have picked up because of previous bad experiences. Not all lace is scratchy, molded cups are not always preferable to seamed cups even under thin knits, demi/balconnette styles are not just for the young and slender, and a bra on sale is not always a bargain. My holy grail of a bra that I found in my mid-fifties is a lacey balconnette, seamed cup, underwire that looks like a wisp of fabric but shapes and supports my breasts while being so comfortable I could wear it for 24 hours without being aware I've got it on. It's a pricey European brand, but it is still holding up nicely after three years of 2-3x a week usage.
So, to answer your question, yes, there is a comfortable, supportive bra out there, but you've have to spend some time and effort finding it. Use a fitter, but trust your own judgement and don't be willing to settle. You, and not the fitter, get to make the decision about which bra is the perfect one for you.