Hi again

Have a number of side quests open along with main quest. (about 5 in total).

Although I can toggle the quest title on and then also the specific task in the right pane I'm unable to pinpoint the location. When I hit x (xbox) I just get a dull thud sound. The result is that although the quest is activated in the quest log, it doesn't show up on the map so I can''t continue it.

Any advice would be greatly appreciated.

Thanks

Simon

What quests are these?
Not all quests have quest markers for all objective. Those quests where you have to find or gather a number of items for example. Or No Stone Unturned.
Do you have the Dragonborn DLC? Radiant quests can get a target on Solstheim, and since that's in a different worldspace, the marker won't show up as long as you are in Skyrim.

It seems a bit weird that none of five quests have map markers though.

Sometimes when the map opens up, the quest location is not on the part of map that you are looking at, the arrow will be at one of the very edges of the map pointing the direction that you have to go, PC. pan the map in that direction, and go in that direction.

None on the map, unusual for all locations.

There is a setting in the game-play settings to turn floating map-markers off, don't know if that would affect it.

Do you have the setting turned on to enable quest markers??