My neck is painful including the shoulders l need to know what is causing it?

See your doctor : Needs to be examined and you may need tests such as X-ray maybe MRI and blood tests depending on your situation and what the doctor finds when you're examined. Suggest you make an appointment

Muscle strain: The most common reason is a muscle strain. A good massage and over the counter anti inflammatory medication is often the best course. If still present after 4 weeks seek out a professional opinion.

See answer: It's impossible to diagnose the specific cause of your pain given just one sentence of information. Cervical pain involving both shoulders suggests Fibromyalgia or bilateral Cervical Radiculopathy(less likely) among other possible causes. For a specific diagnosis you need to see your physician for an exam.