What makes your belly and sides feel tight all the time and feel like you have a big rock in your belly and hurt in the middle of your belly?

Many possibilities: Not much extra information about you to help you. Do u have history of heartburn? Is discomfort associated with empty stomach and improve after eating? Did pain worse with fatty foods like fry type? Wake you up at night? Back irradiation? Nausea, vomiting? Are you overweight or diabetic? Could be gallbladder disease, gastritis, peptic ulcer disease, esophagitis from gerd, angina. See a doctor.