Not very comfortable to drive. Review on Bajaj Pulsar

I bought this bike exactly one month back, and have driven around 650KM so far. I bought this bike for following reasons:

a) I wanted a 150CC bike (I never owned any bike before).

b) Wanted to go for long drives (75KM atleast)

c) My brother already owned Honda Unicorn and so preferred anything else

d) Owing to the reputation and recommendations from my friends, I chose Pulsar

e) I had driven first gen pulsar and felt very good and easy to drive

The pros are obvious (listed in the PROS: section)

But the real show-stopper is the comfort while driving. While test riding some of my friends bike did not reveal it, but after I drove my bike for 25KM on a stretch (from my home at Chromepet to Mayajaal theater in ECR road, Chennai, the road which is extremely good to drive for), I felt acute pain around my neck!., . :((.. Total milege of the bike being less than 1000KM, am driving at a speed of 50KMPH constantly, and so its taking more time for long distances, and this adds to the pain.

After spending more than 65K on my first bike, the thought that its causing me aching me, pains more..

Can someone tell me a remedy for this? Will it be OK to shift to frst gen handle bars (which I have tried and proved fruitful earlier).. is this possible? I dont give importance to looks against comfort.. asked a local mechanic, if shifting to old handle bars is possible, and he said it can be done.. but I wanted to take a few more thoughts to any other possible solution..

My height is around 173CM and I weigh around 78KG.. Hope these details help someone to sortout my problem..

Any reply is highly appreciated..