If you can touch your neck you are mobile enough to start front squatting.
Zombie squats to feel bar position on the front delts. If you clavicles/shoulders/other boney prominences are being destroyed probably racking it slightly wrong.
Progress thumbs, one finger at a time, all fingers, full clean grip and closed fist clean grip over time.
Gets easier as time goes by. Doing the movement a lot improves your flexibility and continuing to do the movement maintains it. After some time off from front squats is always a bitch the first few weeks as everything has stiffened up.