Marinate the chicken at least 2 hours or up to 24 hours.
Soak 6 wooden skewers in water for 10 minutes.
In a bowl, add garlic, oregano, rosemary, paprika, salt, pepper, olive oil, and lemon juice. Add chicken and toss to combine. Cover and Refrigerate for 2 hours.
When ready, thread marinated chicken pieces, pepper, zucchini, and mushrooms through the prepared skewers.
Preheat outdoor grill or grill pan on medium-high heat. Place chicken skewers on grill or cook in batches on a grill pan until well browned and internal temperature registers 155° on a thermometer. (if cooking in batches keep in a 200-degree oven until you are ready to serve) Be sure to turn skewers evenly to cook on all sides. Adjust temperature of grill if necessary). While grilling, brush lightly with the marinade (then discard any left marinade).
Transfer skewers to serving platter and let rest for 3 minutes before serving.