So, I added the following to my http.conf file:
Listen443
NameVirtualHost *:443
<VirtualHost *:443>
DocumentRoot /PATH_TO/www
ServerName www.domain.com
SSLEngine on
SSLCertificateFile /PATH_TO/domain.crt
SSLCertificateKeyFile /PATH_TO/domain.key
SSLCertificateChainFile /PATH_TO/intermediate.crt
</VirtualHost>
https://www.domain.com works now, but it displays the PHP source code? What could be the reason for this?