Is it true, that if you have more muscle, your body is more likely to cramp up? (i mean leg muscles, six-pack) (for a 5'3 female, 225 lbs?

No. Larger muscle mass is a cause of cramps. Cramps are usually due to electrolyte imbalance. Even for a muscular person, you are overweight and losing weight would improve your health! For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine.