Hello!!! I never went for yoga classes and never tried yoga before. But with a friend we tried halasana for fun…and I hurt my neck I have pain while turning my heads to right or left…and pain at the shoulders. Is this serious?? Is there any ways to treat it naturally by any stretches?? Does it need medical treatment?
Halasana or any inversion should be first practiced under an expert’s guidance. People with back problem, neck pain, especially arthritis of the neck should avoid this posture.
Considering you have pain after practicing the posture, there is a possibility that you have most likely put pressure on the cervical spine (neck) thus it is feeling strained.
On the contrary, the neck and back should feel relaxed in this posture. As mentioned, it is important to learn this posture’s alignment from a teacher and also practice it under their guidance.
To be safe, they also recommend the use of props like blanket to cushion your shoulders or wall-support , etc. And a counter-pose like Matsyasana as soon as you come out of Halasana.
If it is a neck sprain and you feel better within couple of days great. If not, please get a medical evaluation and do not try any other stretch until you have understood the cause of pain/discomfort.
If you want to practice this posture, please learn it from a qualified yoga teacher.
Especially for older students. Head stand should not be taught in any Western Yoga school. I know of at least one instance of a person having a stroke during headstand!
I understand your problem. Probably you are already better with you neck but perhaps you are still interested in doing halasana, without hurting your neck? The best and securest way to to halasana is by activating the spine, principally in the middle, the manipura cakra. You can observe that dynamic and some variations in this video: https://www.youtube.com/watch?v=CWJe6a5x2XQ
Good practice wishes you
Narayani
Try looking on a site called posture.tech.. they have loads of articles and info. They also have a posture corrector brace i wore when i was starting my yoga journey - helped my yoga MASSIVELY and will help your shoulder too. Mine came with this free booklet aswell. With simple shoulder opening stretches, yoga sequence and workout 
If your just starting yoga that would be great for you to practice at home for a few weeks