  In the framework of the coupled channel model the mass shifts of the
$P$--wave excitations of $D_s$ and $B_s$ mesons have been calculated. The
corresponding coupling to $DK$ and $BK$ channels is provided by the effective
chiral Lagrangian which is deduced from QCD and does not contain fitting
parameters. The strong mass shifts down for $0^+$ and ${1^+}'$ states have been
obtained, while ${1^+}"$ and $2^+$ states remain almost at rest. Two factors
are essential for large mass shifts: strong coupling of the $0^+$ and $1^{+'}$
states to the $S$-wave decay channel, containing a Nambu-Goldstone meson, and
the chiral flip transitions due to the bispinor structure of both heavy-light
mesons. The masses $M(B^*_s(0^+))=5710(15)$ MeV and $M(B_s(1^{+'}))=5730(15)$
MeV are predicted. Experimental limit on the width $\Gamma(D_{s1}(2536))<2.3$
MeV puts strong restrictions on admittable mixing angle between the $1^+$ and
$1^{+'}$ states.
