Are you using pregnancy pillow? It cushions your hips, depending on how you place your body on it. I used it from late first trimester, naturally sleep on left side (since I was a baby myself according to my mom 😂) and I hadn’t had any aches yet during pregnancy so perhaps it helped? Maybe my left shoulder is a bit achy but I think it’s cos my head didn’t align properly on the pillow.
I honestly think it is ok to sleep however you want, as long as you’re able to sleep well and comfortably. I find it hard to believe it matters so much when historically, women have given birth successfully without caring which side they sleep. Some doctors don’t prescribe this to their patients as they do not think the findings are convincing enough 😅