Apr 27, 2016 - 4:42 AM
Welcome to MySwissAlps, Harvin!
Of course there are plenty of options for a 5 day trip. I don't know how thorougly you've explored the Interlaken and Lucerne areas before. If not, you'll still have quite some options there I think. You can visit the pages I linked to for ideas.
If you prefer to explore another region, then the Valais is an option for sure. Zermatt though is located quite high and may not be the best option for that reason. Mid-May is still a bit in-between seasons there, and pretty much all viewing points are at high altitudes. Staying in or near Montreux along Lake Geneva (not in the Valais, but quite close to it) might be a good alternative. There are quite some viewing points that aren't too high, boat trips can be made over the lake, there's the Chillon Castle, the Lavaux vineyards which can easily be explored by train or on foot, etcetera.
Our planning section may be of help too. You'll find tips and sample itineraries there.