import promblem when field contain comma

Yes, that's normal. You can have several categories separated by a comma.
You will have to use something else than the comma if you don't want that or you should do it differently.
For example, you could create that category and then have the category id instead of the category name in the categories column of your CSV.

Then you should have the text of the column like that: "soap ""sheep"""
The first " and the last will delimit the data of the column and the "" will be converted to " during the import.

Please replace the line:
$newProduct->$field = trim($value,'\'" ');

by:
$newProduct->$field = preg_replace('#^[\'" ]{1}(.*)[\'" ]{1}$#','$1',$value);

in the file administrator/components/com_hikashop/helpers/import.php and try again.

It's probably your HTML editor which strips out the tags because it's working fine on our end.

Then I have no idea.
Can you do an import while having the debug mode of the joomla configuration activated and give the traces printed at the bottom of the page ?

You can use tab or comma or semi colon as field separator. Also, If you have double quotes around your fields, you can even use the same character as the separator in the value of the field.

For the import, it's detected automatically.
For the export, there is an option for that in the Files/Images tab of the configuration.