There are several different possibilities here.
If the sensitivities is generally over a relatively large area of skin, then one possibility would be that you are experiencing some dryness of the skin, perhaps from frequent showering or cold weather. You might want to try using a good moisturizing lotion and seeing if things clear up.
If you have any itching or redness, another possibility would be eczema
or contact dermatitis, two condition in which the skin becomes inflamed. Contact dermatitis is usually caused by a new personal care product, such as a new detergent or soap, whereas eczema is more related to stress and dryness of the skin. Both condition will respond to over the counter steroid creams like hydrocortisone as well as, in the case of contact dermatitis, avoiding the offending agent.
If the sensitivity is just on one side of the body, another possibility is an early sign of a shingles attack, which is a reactivation of the chicken pox virus that tends to cause strange sensations or pain on just a narrow strip on one side of the body, sometimes associated with blisters.
I recommend that you make an appointment with your primary care doctor
to discuss the issue. Good luck.