Sounds like you’re a candidate for made-to-measure shirts. I’m going to assume that you don’t have a good-fitting shirt right now, so I’ll recommend you use a program that will have a real human being take your measurements.
Personally, I’d recommend MyTailor.com. Check out their traveling tailors’ schedule and book yourself an appointment. I’ve reviewed them in the past, and really liked the outcome.
There’s also J. Hilburn, which will measure you up in person. I’ve had no prior experience with them, but other bloggers (google around for reviews) have had decent enough experiences.
Now, if by some chance you’ve got a shirt that fits you good in the neck, across the shoulders and through the torso (ie: your chest measurement is pretty on point with the shirt), then you could consider just using other online MTM sites. All you would have to do is enter in longer sleeve lengths and shirt lengths into the measurement boxes.
There’s a lot of option for places like this: Biased Cut, Cottonworks, ModernTailor, etc. If you’re comfortable with entering in your own measurements, then that’s probably the quickest route. I’d highly recommend taking measurements off of a “good-fitting” shirt and tweaking it for the lengths you need rather than trying to measure your body.
Best of luck!