Getting baby to put him self to sleep 😏

Vera
So my baby is 4 months old almost 5. I can't seem to get him to sleep on his own,  he cries so hard that he throws up. All but one nap during the day are like 30 mins long.  he will take one nap from 1:30 to 4, but that's only if he is in my arms. The min I put him down he wakes up. I started work again mind you I work from home, but need to be on the computer the whole time. My back and neck are beinging to hurt it's hard to scoot down in the sofa while holding him and working with one hand. Help anyone have ideas, I can't let him cry and throw up and just leave him there lol 😭