This is completely normal. Guinea pigs tend to have a funny five minutes just like dogs and cats do when they are excited, it indicates that your pet feels safe in its home but when you try to take it out it will act timid until it gets used to you. This behavior is more ofter found in males!
As for the chewing on the bars of its cage you can buy sprays in pet shops that you apply to the cage and it prevents the pigs from chewing on it
As for the chewing on the bars of its cage you can buy sprays in pet shops that you apply to the cage and it prevents the pigs from chewing on it