As a LAQ I get quilt tops that are made of different grades of cotton. Some pieces have more stretch than others. This isn't so noticable when the top is being made or ironed, but when it gets pulled taut on the quilting frame the looser weave or stetchier materials show up.
All that said when you wash a quilt and there is a degree of shrinkage, they often puff up. Unless its patchy on yours I wouldn't worry about it. 5 inches between stitch lines is not bad. If you try to SID you may do nothing more that push the offending looseness into the center and make it more puffy. Remeber we are the worst critics of our own work.
If its your work as a gift go ahead and wash it and see what happens.
MaryKatherine