Stress induced illness and anxiety and muscle tightness can definitely be worked with through yoga practice:
Hatha yoga is the term used for the type of yoga practice where the mind is accessed, brought into focus and serenity, through the use of asanas. Sometimes this will or can be, a vigorous practice, other times it may be restorative yoga and other times, balanced. Whether you are practicing one-one, in a group, or on your own, the connection that takes place can be very subtle, as in getting the chance to hear your own instincts. “Serenity comes when you trade expectations for acceptance.” Being present with yourself in class is the best way to honour your body and its limitations. When you do this routinely, you build a sense of confidence and trust in yourself which is a pretty useful tool off the yoga mat as well.
Stress induced illness and anxiety and muscle tightness can definitely be worked with. If you are on the fence about starting, the patient progress you will make in a private yoga class is encouraging and may be just the ticket.