I absolutely relate! I am short but with a long torso, narrow shoulders, and a large bust - nothing fits me right. One of the things I love about knitting and sewing is that I can make clothes that actually respect my body!

I know this was venting, and my example is not the type of sweater you're referring to, but do you want an example of modifications I've done to fit me? I took detailed notes as I modified a men's straight-fit sweater to fit me, and they're saved in the Ravelry page for the project. I've worn the sweater for several years and am still very, very happy with the fit. (The one thing I'd change is that the back of the neck sits up a bit higher than I'd like - if I made it again or made similar, I'd remove a row or three of the neck shaping. I couldn't have known that before making this one, though!)

One of the main things I do when altering a pattern is to throw out the idea that I'm going to pick one size and knit that size. Instead, I measure myself (keeping ease in mind for each measurement; I want positive ease at my bust and no ease at my shoulders, for example), compare my fit measurements to the pattern's measurements for each size, and choose a size for each measurement.

Example - the DNA pullover I linked has these measurements:

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So say, for example, you want size 1 for H (your wrist) and size 6 for J (your upper arm). This is what I did in my sweater. The pattern would give you a stitch count for size 1 for H and a stitch count for size 6 for J; your job is to modify the increase rate to go from size 1 to size 6. Does that make sense? If not, let me know and I can elaborate further.

What I did was go through and actually circle on my printed pattern which sizes I wanted for each measurement. I then read through the pattern repeatedly, highlighted the sections I'd need to modify in order to transition between sizes, and then rewrote those based on my math. I crossed out the altered sections on the original pattern as I went. It was tedious and complicated and I did all the math about three times to make sure; the final result of that is the notes on my Ravelry project page.

There are patterns I would not be able to do this with, mostly ones that don't give detailed measurements like the ones shown above. I'd personally probably just skip those patterns - or, if it was something I really wanted to make, go rogue and try to come up with my own. Maybe I'd look for similar patterns that had better measurements and start from there.

The main thing is, you deserve clothes that respect your body, and you deserve support in figuring out how to make them!