A tender, or sore scalp can be caused by many things. You might be overworking your hair by brushing too hard or pulling your hair into styles that are too tight. More serious causes can be ringworm, or scalp psoriasis. In the case of psoriasis, extremely dry skin is causing the soreness. You might try using moisturizers. This might work for a short time, but since psoriasis is a condition that exists inside your body, treating it from the outside will only give temporary relief. If you are experiencing a sore scalp, try increasing your water intake before jumping to conclusions about the cause. Light dehydration can cause scalp discomfort. If the symptom worsens or is accompanied by other signs of scalp psoriasis, consult your doctor for treatment.