23 weeks pregnant

I'm 23 weeks pregnant and I'm getting this sharp burning pain in my breast bone when ever I lie down, at first I thought it was my bra being to tight but it isn't, iv had this for 5 nights now. Its not a major concern but it is very painful, when I twist and turn its still there, its like a dull ache in my chest bone between your boobs but it only happens when I lie down, I googled it and it said it could be due to my ribs opening. Just wondering did anyone eles get this?