When replacing disc pads on my Giant Boulder I noticed that the front wheel didn't spin freely. Releasing the quick release allowed it to spin thus confirming brakes not binding.

I took the axle out, checked everything, and put it back leaving the bearings looser than I normally would. At first the problem seemed not as bad but still there but within an hour it was as before.

My guess is that the quick release hollow axle isn't strong enough and is bending.
Is this likey?

Should I get a better quality of axle (anyone suggest a good brand?) or should I change to a solid axle?

Is this a common problem? On investigation I found that the back wheel is similarly affected though not as badly.