i found what causes it.
In some cases, lack of hygiene may be a reason for tender, itchy scalp. In other cases, excessive use of hair care products that contain harsh chemicals can be the cause of tender scalp. Most shampoos consists of an aggressive foaming and cleaning agent namely Sodium Laureth Sulphate (SLS). The chemicals remove the natural sebum from the scalp and affect the pH balance. These natural oils are essential to protect the scalp from several fungal infections. When the skin becomes tender and dry, it may become susceptible to yeast organisms such as Pitysporum Ovale or Melassesia Globbosa. Due to yeast infections, there may be flaking and dandruff formation. Acne is also the common cause of tender scalp. It may result from infection, ingrown hair, hormonal causes, blocked pores and incorrect diet.
A fungal infection by ringworm (Tinea capitis) is one of the main causes for tender, sore scalp. This infection is more commonly seen in children. It is a superficial yeast infection of the scalp and it is caused by mold-like fungi known as dermatophytes. It causes the symptoms such as itchy, red patches on the scalp, resulting in hair loss and development of bald areas.
Your scalp may become tender due to an allergic skin reaction (contact dermatitis). There are two forms of allergic reactions such as irritant contact dermatitis and allergic contact dermatitis. Allergic contact dermatitis is a type of hypersensitivity reaction, resulting from the body’s immune system. Irritant contact dermatitis is developed due to the direct effect of irritant substances on the skin.
Certain viral infections such as chickenpox or shingles can also cause tender scalp
Use of products containing natural ingredients such as wheatgerm, macadamia or jojoba oils are recommended. These oils remoisturize and nourish the scalp. You can also massage the scalp using some natural oils such as lavender, chamomile, eucalyptus or avocado oil, which have soothing, healing, antibacterial as well as antifungal properties.
Tender hair follicles may result from too tightly tied hair.
i got all this from http://www.buzzle.com/articles/what-causes-tender-scalp.html
i bolded the things that are most likely causing your scalp to be so tender and other oils that help just in case you didnt want to read all that.