Baby naps in swing??

B17
Ive been letting my 3 and half week old nap in his swing during the day. His naps last about 2-3 hours long. About 3-4 times a day.. I always wake him to feed every 2-3 hours.. But is it ok to let him spend so much time in his swing? Like will his back be okay? Sorry if thats dumb.. Just dont want his back hurting or turning to mush or whatever. :p