I am using TwitterOAuth to get the tweet count of a hashtag but there is one issue; It only returns maximum of 100 results.
I want to get all tweets of a hashtag. Is this possible? Is so, how?
I assume you are using get parameter on this url as you haven't shared code.
https://api.twitter.com/1.1/search/tweets.json?q=??&count=??
So you need to specify count here which is described in following twitter api docs.
https://dev.twitter.com/docs/api/1.1/get/search/tweets
Yes there is 100 count limitation. So in that case page parameter can be added but twitter has written why timeline option is better.
https://dev.twitter.com/docs/working-with-timelines
So answering your question you will using query something like this. This will give 2nd page with 100 results. Read the link above to use options like max_id and since_id.
https://api.twitter.com/1.1/search/tweets.json?q=google&count=100&since_id=100
This way extend your 100 results limit and you can always test your query on