If neck or shoulder pain nags you, or rounded shoulders has become your work-from-home posture, the rhomboids could be to blame.
The rhomboids are comprised of two separate muscles—the rhomboid major and rhomboid minor. They are part of the shoulder girdle musculature and they serve as scapular stabilizers while also contributing to upper limb movement. They work with other muscles to stabilize the scapula on the rib cage during weight-bearing movements; pulling motions, such as rowing, are the result of the rhomboids and trapezius working together.  
The rhomboids are commonly underdeveloped and elongated. This can contribute to a rounded-shoulder posture and is commonly seen in people who work at computers or otherwise maintain forward-arm positions for long periods. When the scapula is held in a protracted and depressed position, the rhomboids elongate and the serratus anterior shortens. This creates muscle tension and 
decreased mobility in the shoulder girdle and cervical spine that is perceived as neck and shoulder pain or stiffness. Maintaining optimal length and strength in the muscles of the shoulder girdle contributes to healthy alignment and mobility in the upper body. 
Here are some movements to help you maintain healthy rhomboids and avoid rounded-shoulder posture.

Active Scapular Movements

1. Sit or stand facing forward with your arms at your sides and shoulders relaxed. 
2. Begin by shrugging one of your shoulders, shortening the distance between your shoulder blade and back of your head. Do not move your arm, just the shoulder blade. (Image A)
3. Next, keeping your arm at your side, push your shoulder blade down and away from your head. (Image B) 
4. Return to neutral then squeeze your shoulder blades together. (Image C) 
5. Next, pull your shoulder blades as far apart as you can. (Image D)
6. Repeat all.

Christy Cael is a licensed massage therapist and certified strength and conditioning specialist. Her private practice focuses on injury treatment, biomechanical analysis, craniosacral therapy, and massage for clients with neurological issues. She is the author of Functional Anatomy: Musculoskeletal Anatomy, Kinesiology, and Palpation for Manual Therapists (Lippincott Williams & Wilkins, 2009).