For purposes of legislative history research, hearings focus on the views of the parties testifying before Congress, and do not necessarily reflect the views of the committee or Congress.
House and Senate committees hear testimony on proposed legislation in order to determine the need for new legislation in a particular area and to hear the views of various persons or organizations interested in the legislation. Hearings can provide a wealth of information for background research into the issue Congress is addressing. Hearings are held for almost all substantive legislation and transcripts of most hearings (including exhibits provided by those testifying) are published. For interpreting enacted legislation, hearings are less useful than other legislative documents because they focus on the views of the parties testifying rather than the views of the committee or Congress.
For very recent hearings you may find that transcripts are difficult to find. First, note that you may be able to obtain hearing materials from the committee website itself. The Federal News Service (available via Westlaw) also transcribes selected hearings and uploads them daily. A final source to check for recent hearing transcriptions is CQ Transcriptions on Nexis Uni.
You may also be able to find video recordings of hearings at C-SPAN.org (sometimes these have search-able closed captioning, though be aware that this captioning may contain spelling errors).