What can your babies do at 4 months old? My little one (two weeks ago)…

What can your babies do at 4 months old? My little one (two weeks ago) has only just started holding her head up on her tummy for longer, usually every turn was an outburst of crying. Now she holds her head up on her tummy for no more than 3-4 minutes before lowering it, and when she raises it again she coughs and asks to be turned over onto her back. She grabs objects only when lying on her back. She doesn't grab them when lying on her stomach. How is this with you? We have just celebrated our four month milestone. Maybe we should forcefully put her on her tummy and let her cry, but I feel so bad for the child...