I was bored while watching the series.
At that time, you had that state. We have no idea when or why your boredom began, only that it overlapped your viewing of a television program. This might imply that you didn't pay much attention to the show because you were already bored.
I got bored while watching a series.
At that time, you acquired that state. Your boredom began during the show. This might imply that your boredom is the result of the show.
His father gave him the cell.
This has nothing to do with when his father acquired the phone. This action is the son's acquisition.
His father got him the cell.
This has little to do with when the son acquired the phone, or even whether he has. This action is the father's acquisition. It's possible that the father got the phone as a gift for his son, but the son doesn't have it yet.
She got married to John.
That implies a wedding. Marriages generally start with one.
She was married to John.
That might suggest a divorce. Without further context, it places the entire marriage in the past, not just its beginning.