Is it normal to have Braxton Hicks every 5-30 minutes?

I’m only 28 weeks but I’ve been having these Braxton Hicks contractions since last week. What concerns me is that they come pretty frequently. Sometimes I would feel them several times an hour, sometimes only 5-10 minutes apart. But they’re not regular. Sometimes I only have 3-4 in one hour. From what I heard, they should only come once or twice an hour. Am I having too many of them? Does this mean I’ll have true labor soon? I’m not sure when it will be concerning enough for me to go to the doctor?