I can barely sleep on my side without shoulder pain

Side sleeping at your weight usually means you need something that lets your shoulder sink in enough to align your spine, but not so much that your hips bottom out. A medium-firm hybrid with a thick comfort layer might do it. What's your current mattress?

I had the same issue. Turned outt my pillow was too thick, pushing my shoulder up. Switched to a thinner pillow and the pain eased within a week. Might not be the mattress at all.

Memory foam toppers tend to bottom out under heavier sleepers. Look for a mattress with a support core of pocket coils and a latex or high-density foam top. Latex is more responsive and won't let you sink as much.

I’m 245 and a side sleeper. I ended up with a Sleep Number bed because I could adjust the firmness per side. It’s expensive but it solved the shoulder pain. You can also try putting a small pillow under your waist to keep your spine neutral.

Have you considered sleeping on your back? I know it's hard to change, but side sleeping will always put pressure on one shoulder. A body pillow behind your back can help you stay off the shoulder.

Don't ignore the foundation. A sagging box spring or slats that are too far apart can make any mattress feel unsupportive. Check that first before spending money.

That dip is a killer. At 270 lbs, a cheap innerspring will break down fast. Look for something with a coil gauge around 13-14 and high-dens ity foam (at least 1.8 lb/ft³). Avoid anything with low-density memory foam.

MossyStone makes a good point about the pillow. But with a 7-year-old sagging mattress, you're fighting a losing battle. A medium-firm hybrid with zoned support could help, but you might also try a mattress topper designed for heavy people—something like a 3-inch latex topper. It wont fix the sag, though.

Yeah, if there's a dip, the topper will just follow the dip. Time for a new mattress. Also, try sleeping with your lower arm extended in front of you rather than tucked under your pillow. Reduces shoulder pressure.

I’m a big guy too and I went with a Titan mattress. It’s built for heavier sleepers and has a firmer feel. Might be worth a look. Not cheap but my shoulder pain is gone

Before you buy, try putting a folded towel under your ribcage to lift your torso slightly. It can take pressure off the shoulder. Cheap experiment.

Another thing: side sleepers often need a softer top layer so the shoulder can sink in, but a firmer core for support. That combination is hard to find in budget mattresses. If you go hybrid, look for one with a soft cover and medium-firm coils.

I've heard good things about latex for heavy side sleepers. It's buoyant and doesn't heat up. But it's heavy and expensive. Maybe find a store that lets you try it for 30 nights.