It's hard to give you a complete answer without knowing what you mean by "locking problem". All queries take locks of one type or another and this is normal and correct. I'm going to assume you mean that queries are getting blocked? Where you are running one query and another will have to wait for resources?
I can tell you the following:
- While you create the indexes you might (depending on how you create it) see some blocking.
- Every index you add creates overhead for write operations. This means that your writes will take longer and could increase the amount of blocking that you see.
In and of themselves no, creating 5-6 indexes shouldn't be causing you a noticeable problem. Now if you had 50-60 indexes we might expect one. If you are seeing a problem you will have to give us quite a bit more detail (table structures, indexes, queries that are having a problem, and most importantly what the actual problem is) before we can give you a more specific answer.