No. You can do-it-yourself. Visit Seal and Insulate with ENERGY STAR for more details. Look for the Do-It-Yourself (DIY) Guide to Sealing and Insulating for help. Once you know what to look for, you can seal air leaks all around your home on your own. When everything is sealed, adding insulation to your attic will make your home more comfortable.
On the other hand, you may prefer hiring a knowledgeable contractor to help. Contractors have experience along with tools and instruments they can use to find problems areas quickly. They also know the proper materials to seal leaks and can add insulation efficiently. Consider using a Home Performance with ENERGY STAR contractor if a program is available in your area.