  The resonances, containing $c\bar c$ plus $s\bar s$ (or light $q\bar q$)
quarks in the mass region $(3900-4700)$ MeV, are analyzed in the relativistic
strong coupling theory, with and without channel coupling phenomena. The
conventional charmonium spectrum is presented, being calculated with the
relativistic string Hamiltonian, which does not contain fitting parameters,
while for high excitations the universal flattened confining potential is used.
It is shown that $X(4274),X(4500),X(4700)$ can be identified as $3\,^3P_1,
4\,^3P_0, 5\,^3P_0$ states. The exotic states are considered using the
coupled-channel (recoupling) theory, when two mesons $m_1,m_2$ transfer into
another two mesons $m_3, m_4$ and back (infinite number of times), creating the
four-quark systems. The resonances $X(3875), X(3915), Z_{cs}(3985), X(4140)$
can be explained in this way as the exotic four-quark states in the $S$-wave
decay channels.
