I have a memory foam pillow in the cupboard.
Your neck/upper back can get sore from spending too long in a bent-forwards position, so a single pillow is better than two, as it avoids forcing your neck forwards. I found the memory foam pillow fine for lying in one position on my side, but no use on my back, or moving around.
At the computer, I find that leaning forwards, whilst also tipping my head backwards to accommodate the varifocals is a killer. Really, it is best to adjust the chair, keyboard and screen so that you have good posture and engage all your tummy/back muscles correctly and shoulder and muscles can relax. Sometimes, it can help with the varifocals if the screen is tilted slightly. Take time to do the neck muscle exercises and relax shoulders/neck at regular intervals.