How to compute the channel gain from the path loss model of a wireless channel I did my research but I did not get a satisfying answer. 
We have a transmitter and a receiver over a wireless communication channel. The channel's path loss is modeled as 
$ 128 + 37 \log_{10} (d)$, with a shadowing standard deviation of $10$ dBs. 

I am assuming that this path loss equation is expressed with dBs (nothing explicitly says that). 

I have read that the combined path loss and the shadowing model is just the addition of the path loss model and a normally distributed random variable with mean $0$ and std. $10$ dBs.


Is this addition of path loss and shadowing is the same as the channel gain ?
If not, how to calculate the channel gain $\vert h \vert$ from the path loss model, combined with the shadowing ?
To answer the literal questions you asked:


yes
see above


To Frame Challenge your question and give you what you were probably looking for:  

The path loss equation you cited:
$$
128+37\log_{10}(d) ,
$$
is equivalent to:
$$
\frac{P_r}{P_t} = \frac{10^{-12.8}}{d^{3.7}},
$$
where $P_r$ is the received power in Watts, and $P_t$ is the transmit power in Watts.  From this equation it can be seen that the path loss exponent is 3.7. 

Under log-normal shadowing, the random shadowing component is modeled as a zero-mean Gaussian random variable (in dB) added to the path loss.