No u shouldt be worried atall its normal espically when its braxton hicks if it gets stonger and faster then u should go and checked out espically if you start bleeding but you should be fine
Braxton Hicks will not normally have a set pattern to them. While they CAN be moderately intense and sometimes even sort of painful, they will be shorter in duration and will NOT increase in frequency.
Unless you have them where they last a minute or more in duration and they become more frequent and more regular (like they go from 45 seconds from start to finish and come every 15 minutes to lasting 1 min 20 secs and come every 8 minutes) That is when you should call your OB or go to L& D if you are still before 37 weeks. After 37 weeks they typically say to wait until your contractions are 3-5 minutes apart before going to L & D. Your doc will have his/her own set of recommendations so speak with him/her to see what they are.
Anytime you feel yourself questioning if something should be worrysome or not, it's always good to call your doctor and find out what S/HE thinks you should do. This will give you some peace of mind and it's what they are there for. Good luck!