First please use the code icon (<>) in the menu for your code and specify PHP.
1. How did you define the password column in MySQL?
2. How did you store the password in the database?
3. Assuming you used 'password' to do the store you must use the same function in the query to retrieve the row.
4. 'password' is a MySQL reserved word so you should avoid it for a column name. If you do use it, you must always enclose it in back ticks(`) in your queries.
As an aside, I suggest you use PDO as it is easier and more flexible. You should also never use post data directly in any MySQL query. Validate it and use prepared statements.