Neck is a problem in that the muscles have to be trained. It also helps if there is not a visor on the helmet. I always wondered why roadies did not use visors and found out when I took mine off the MTB helmet.

But the back. It makes sense to raise the bars and shorten the reach. This may also help on the neck. But some of us find that a more stretched out ride position helps. Helps take the strain off the vertebrae so before you commit to N+1 try a few things out. If it is in the drop position that the back ache comes in- Practice going into that position. I know when first got a road bike- I could not use the drops. 20seconds in that position and I was in agony. I always rode on the top of the bars or on the hoods. So every ride I would force myself into the drops. not long- just till the pain started and then on the tops. But I did this frequently. A Few rides later I hit a headwind and used the drops- For about 5 miles with just some discomfort so practice works for some backs.

Raising the bars may help- but that first bike had the bars level with the saddle. It was never fully comfortable- but the 2nd bike and the shop set it up with the bars 4" below the saddle. I had my doubts but the shop told me to try it. I did and the low bar coupled with a longer top tube to stretch the back out worked. Only get back ache after many hours in the saddle now and am able to use the drops as often as I want for as long as I want. Still favour the hoods to ride in but that is one comfortable bike.