Hi carocaro
IMO, defn worth going to your GP & asking for a referal to phsio for torticollis. Dd had it mildly (only diagnosed at 6 mths, although missed by our CO) - and as I understand it, true tort rarely just sorts itself out (& obviously, as long as your ds doesn't look to the other side, the head asymetry isn't going to sort itself out.
Lots of what we were told wasn't rocket science - eg hold toys to the RHS, position everything interesting to RHS etc, buy there are also some stretches that can help - if you google torticollis there are some good ones online. DS also had a strong perefence to look one way - hv dismissed it, my mates through I was mad, but i did a lot of work putting things to his 'wrong' side and sorted him out on my own
We also used Bowen therapy (no idea HOW it works, complete mumbo-jumbo!) which really helped dd.
At this stage, you should be able to make a big difference pretty quickly to your ds' head shape, if you can get the tort sorted. You might want to think about some repositioning techniques to keep him off his flat spot (eg carry in sling; prop him slightly with rolled blankets in his buggy) - there are also repositioning products/techniques you can do when they're sleeping, but all involve stuff in cot, which SIDs recommend against - can tell you more if you want to go down that route
Lots & LOTS of tummy time will also help (although tort babies tend not to like this much - getting down to his level/putting him over your knee so he can see better will all help
Well done for spotting it so early