Short answer: no one really knows. God, anyone?
Long answer: Theories abound,
http://hyperphysics.phy-astr.gsu.edu/hbase/particles/hadron.html#c7
This site states that "the current view is that the strong interaction is an interaction between quarks."
It causes the protons in the nucleus repel each other.
There is a nucleus inside a proton.Protons are part of what is the nucleus, so the answer is rather: inside.
The nucleus consists of protons and neutrons. Inside the nucleus, there is an electrostatic force of repulsion between the protons. Those protons have positive charges, and like charges repel. Also acting in the nucleus is a force of attraction called the nuclear force. It provides the nuclear binding energy to keep the nucleus together. This nuclear force is a short range force, and is so strong that it will overcome the effect of the force of repulsion between the protons.
Protons are found in nucleus inside an atom.
The protons are found outside of the neucleus not inside
They are found inside the nucleus
Protons are located inside the nucleus.
Inside a nucleus there are protons and neutrons
The "strong force," or sometimes called the "strong nuclear force." This is the exchange of gluons between the protons and neutrons.
The number of protons in the nucleus is the same as the atomic number.
Protons and neutrons
The nucleus of an atom contains neutrons and protons. Almost all of the mass in an atom is made up from the protons and neutrons in the nucleus. Because the nucleus is only made up of protons and neutrons, it is positively charged. Physicists believe that there is a cluster of Protons and Neutrons within an Atom's nucleus. Friend Premier is quite right. So instead saying inside the nucleus it would be apt to say that nucleus is made up of...