The most likely reason that apache does not start related to ssl are:
1) One of the defined ssl certificate files (crt, key or chain file) is missing.
2) One of the certs is broken (if a singöe char in one of the files is wrong, apache will not start).
3) A ssl cert consists of two files, the certificate and the key. If the key and crt does not beling together, apache will not start.
In all of these 3 cases, apache will not throw an error, it just wont start.
To find the problem, comment ou all ssl vhosts except of one and also comment out the ssl cert lines in this vhost and try to start apache without ssl in this vhost. If it works, enable ssl just in thsi vhost, if it does not start anymore then create a new self signed ssl cert for this vhost and use just this crt and key (no chain) certificate and try again to to find the reason for yozr problem.