Elaborating on biocqr’s post (#msg-123565141)… If you don’t employ an app such as Tweetdeck, there are brute-force methods of finding something on Twitter, but they are rather tedious.
In your example (finding tweets by me pertaining to EGRX), either of the following methods will work:
1. Go to my home page on Twitter (https://twitter.com/DewDiligence ) and use your browser’s search function to look for “EGRX”. If you don’t get any hits, scroll downward and Twitter will display older tweets. Repeat this process as many times as necessary. (You don’t need your own Twitter account to do this.)
2. Log in to your own Twitter account and use Twitter’s search function to look for “$EGRX”. In the menu just below where “$EGRX” is displayed in big letters, click on the “Top” option (which filters out tweets from all but the “top” twitter accounts). Scroll down to display older tweets until you find what you’re looking for.
News 
Market Data 
Discover 
