You better believe it can cause problems. That's one reason why it is so important to have a good teacher when you start so bad posture habits don't start. If taught properly, if the chin rest is fitted correctly and posture is reinforced it's really not a problem. Many teachers have full length mirrors in their studios so students can check themselves. My chiropractor has several violin and viola players he sees for neck and hand issues. Mostly older players who have been at it a long time. And you'll notice some violin players have what looks like a hickey on their neck which is from the contact pressure.