I'm big on ergonomics and even bigger on getting up and moving/changing tasks every 15 minutes or so.
Get yourself a good chair and a good solid surface for your sewing machine. I've seen people using card tables that moved so much it was like being on a bucking bronco and they wondered why they had problems.
Me personally, I have a long torso and short little arms and legs. The "typing tray" level is never the correct level for me, it is desk top. Similarly, my seat on my chair is lower than people expect because my length is not in my legs.
I've found out things over the years, like the best height for me to cut fabric is standing at my kitchen table. My friend who is taller does her best on her kitchen counters.
I've been feeling a bit bad about spreading my quilting stuff out across the house but I've done it for good reasons. I used to keep it all in my sewing room and could easily not get up out of my chair for hours just rotate in the chair from sewing machine to ironing board to cutting table but I'm trying to get a few more steps in each day as part of my on-going battle with health and life style changes. My cutting station is currently on my dining room table, that's easy to get up and out of the way. The ironing board is in the living room. The sewing room is the small middle bedroom, and I layout stuff on the bed in the master. I wasn't wearing my fitbit yesterday but I can tell you -- I got in a lot of steps working on a tiny little project deliberately going from one room to another.